急性巨核细胞白血病的治疗

Acute megakaryocytic leukemia (AMegL) is a biologically heterogenous subtype of acute myeloid leukemia (AML) that arises from megakaryocytes. Improvements in the accuracy of …

To characterize acute megakaryocytic leukemia (FAB M7 AML), we identified 37 patients with M7 AML treated at M.D. Anderson Cancer Center between 1987 and 2003 and compared them with 1800 patients with non-M7, non-M3 AML treated during the same period. The median age of the M7 AML group was 56 years (range, 21-78 years); 22 patients (59%) had an antecedent hematologic disorder or myelodysplastic syndrome or both, and 7 patients (19%) had previously received chemotherapy for other malignancies. Extensive bone marrow fibrosis was found in 23 patients (62%). Poor cytogenetic characteristics were observed in 49% of patients with M7 AML versus 33% of others (P < .001). Complete remission rates were 43% with M7 AML and 57% with non-M7 AML (P = .089). Median overall survival (OS) was 23 and 38 weeks, respectively (P = .006). Median disease-free survivals were 23 versus 52 weeks, respectively (P < .001). By multivariate analysis, M7 AML was an independent adverse prognostic factor for OS, independent of other factors including cytogenetic abnormalities (hazard ratio 1.51, P = .049). These results confirm the poor prognosis of M7 AML and indicate that other biologic characteristics beyond cytogenetic abnormalities likely play a role in this disease.

… The objective of the study was to evaluate the incidence, characteristics, treatment and outcome of acute megakaryoblastic leukemia (AMeL) in patients enrolled in GIMEMA trials. …

… initial treatment. It is our impression that the prevaIence of acute megakaryoblastic leukaemia has been under-estimated, and that low-dose cytosine arabinoside treatment may be of …

Acute megakaryoblastic leukemia (AMKL) comprises between 4% and 15% of newly diagnosed pediatric acute myeloid leukemia patients. AMKL in children with Down syndrome (DS) is characterized by a founding GATA1 mutation that cooperates with trisomy 21, followed by the acquisition of additional somatic mutations. In contrast, non–DS-AMKL is characterized by chimeric oncogenes consisting of genes known to play a role in normal hematopoiesis. CBFA2T3-GLIS2 is the most frequent chimeric oncogene identified to date in this subset of patients and confers a poor prognosis.

To describe the clinical and biologic features of pediatric acute megakaryoblastic leukemia (AMKL) and to identify prognostic factors, experience at St Jude Children's Research Hospital was reviewed. Of 281 patients with acute myeloid leukemia treated over a 14-year period, 41 (14.6%) had a diagnosis of AMKL. Six patients had Down syndrome and AMKL, 6 had secondary AMKL, and 29 had de novo AMKL. The median age of the 22 boys and 19 girls was 23.9 months (range, 6.7-208.9 months). The rate of remission induction was 60.5%, with a 48% rate of subsequent relapse. Patients with Down syndrome had a significantly higher 2-year event-free survival (EFS) estimate (83%) than did other patients with de novo AMKL (14%) or with secondary AMKL (20%;P ≤ .038). Among patients who had de novo AMKL without Down syndrome, 2-year EFS was significantly higher after allogeneic bone marrow transplantation (26%) than after chemotherapy alone (0%;P = .019) and significantly higher when performed during remission (46%) than when performed during persistent disease (0%;P = .019). The 5-year survival estimates were significantly lower for de novo AMKL (10%) than for other forms of de novo AML (42%; P < .001). Treatment outcome is very poor for patients with AMKL in the absence of Down syndrome. Remission induction is the most important prognostic factor. Allogeneic transplantation during remission offers the best chance of cure; in the absence of remission, transplantation offers no advantage over chemotherapy alone.

… Given the overall poor outcomes for AMKL, new treatments are … severe side effects from the therapy. Recently there has been considerable interest in leveraging differentiation therapy …

… 2 patients with acute megakaryoblastic leukaemia (AMKBL) were successfully treated with a … and in complete remission throughout 3 courses of consolidation therapy, a total of 9 weeks. …

Despite recent advances in the treatment of children with acute megakaryoblastic leukemia (AMKL) using intensified treatment protocols, clear prognostic indicators, and treatment recommendations for this acute myeloid leukemia (AML) subgroup are yet to be defined. Here, we report the outcome of 97 pediatric patients with de novo AMKL (excluding Down syndrome [DS]) enrolled in the prospective multicenter studies AML-BFM 98 and AML-BFM 04 (1998-2014). AMKL occurred in 7.4 % of pediatric AML cases, at younger age (median 1.44 years) and with lower white blood cell count (mean 16.5 × 109/L) as compared to other AML subgroups. With 60 ± 5 %, children with AMKL had a lower 5-year overall survival (5-year OS; vs. 68 ± 1 %, Plog rank = 0.038). Yet, we achieved an improved 5-year OS in AML-BFM 04 compared to AML-BFM 98 (70 ± 6 % vs. 45 ± 8 %, Plog rank = 0.041). Allogeneic hematopoietic stem cell transplantation in first remission did not provide a significant survival benefit (5-year OS 70 ± 11 % vs. 63 ± 6 %; PMantel-Byar = 0.85). Cytogenetic data were available for n = 78 patients. AMKL patients with gain of chromosome 21 had a superior 5-year OS (80 ± 9 %, Plog rank = 0.034), whereas translocation t(1;22)(p13;q13) was associated with an inferior 5-year event-free survival (38 ± 17 %, Plog rank = 0.04). However, multivariate analysis showed that treatment response (bone marrow morphology on day 15 and 28) was the only independent prognostic marker (RR = 4.39; 95 % CI, 1.97–9.78). Interestingly, GATA1-mutations were detected in six patients (11 %) without previously known trisomy 21. Thus, AMKL (excluding DS) remains an AML subgroup with inferior outcome. Nevertheless, with intensive therapy regimens, a steep increase in the survival rates was achieved.

… Later on, a significant number of these children relapse with a frank acute megakaryocytic leukemia that belongs to the very same clone as the previous TAM and needs chemotherapy.l’…

… of a group of 5 7 acute megakaryoblastic leukaemia (M7-AML) … were treated with combined aggressive chemotherapy (CT) (… Irrespective of the treatment modality, the results were better …

Acute leukemia with megakaryocytic differentiation has been an uncommonly recognized disorder. We used specific monoclonal and polyclonal antibody reagents (HP1–1D antibody and anti-factor VIII antibody, respectively) and an immunocytochemical staining technique to identify the megakaryocytic nature of the leukemic cells of 12 patients who presented with acute leukemia. The leukemic cells of our patients demonstrated the presence of one or both of these platelet- and megakaryocyte-related antigens, but were negative for all of the commonly employed cytochemical and immunocytochemical staining reactions, except for diffuse acid phosphatase activity and granular PAS positivity. Morphologically, the leukemic cells varied in size from 10 to 40 microns in diameter, frequently had cytoplasmic budding, and contained occasional vacuoles and/or peroxidase-negative azurophilic granules. Five patients presented with syndromes of acute myelofibrosis, and seven patients had otherwise unclassifiable acute leukemias, including three patients who had secondary leukemias. Diffuse reticulin myelofibrosis was present in all cases in which it was sought. Chromosomal abnormalities of leukemic cells were found in five cases. Two patients had deficiencies of plasma coagulation factor V. Study of one patient revealed significant platelet dysfunction. When cytoreductive chemotherapy of leukemia was attempted, the observed response was generally poor, with the exceptions of one patient who has remained in complete remission following treatment with etoposide (VP- 16) and a second patient who attained remission following bone marrow transplantation. These cases of acute megakaryoblastic leukemia represented from 3.6% to 9.3% of all acute leukemia cases diagnosed concomitantly in our institution. Acute leukemia with megakaryocytic differentiation may occur more frequently than previously recognized, may present with differing syndromic features, and can be identified by the use of specific antibody reagents and relatively simple immunocytochemical techniques.

ABSTRACT Introduction: Acute megakaryoblastic leukemia (AMegL) is a rare hematological neoplasm most often diagnosed in children and is commonly associated with Down's syndrome (DS). Although AMegLs are specifically characterized and typically diagnosed by megakaryoblastic expansion, recent advancements in molecular analysis have highlighted the heterogeneity of this disease, with specific cytogenic and genetic alterations characterizing different disease subtypes. Areas covered: This review will focus on describing recurrent molecular variations in both DS and non-DS pediatric AMegL, their role in promoting leukemogenesis, their association with different clinical aspects and prognosis, and finally, their influence on future treatment strategies with a number of specific drugs beyond conventional chemotherapy already under development. Expert opinion: Deep understanding of the genetic and molecular landscape of AMegL will lead to better and more precise disease classification in terms of diagnosis, prognosis, and possible targeted therapies. Development of new therapeutic approaches based on these molecular characteristics will hopefully improve AMegL patient outcomes.

… acute megakaryocytic leukemia (AMkL) have higher cure rates than non-Down syndrome acute myeloid leukemia (AML) patients treated … linkage to the chemotherapy sensitivity of …

… are highly predisposed to acute megakaryoblastic leukemia (AMKL). Treatment outcome is more … The distinct biological features of DS-AMKL are reflected by differences in treatment …

Acute megakaryoblastic leukemia (AMKL) occurred in 89 of 1255 (7.1%) of children and adolescents below 18 years of age without Down’s syndrome enrolled in the population-based …

… treatment intensity has improved outcomes for children with acute megakaryoblastic leukemia (AMKL), the prognostic and therapeutic implications of megakaryoblastic differentiation …

… Considering the presence of GATA1 mutation and good response to cytarabine, we decided to treat him with less intensive chemotherapy for ML-DS [9]. After the second course of …

… The French-American-British (FAB) leukemia cooperative study group, in this issue (1), adds another category of acute nonlymphocytic leukemia to their classification: acute leukemia of …

Antigen expression on residual blast cells in acute megakaryoblastic leukemia (AMKL, classified as AML-M7 by FAB criteria) may change after treatment, potentially affecting both immunophenotypic characterization and minimal/measurable residual disease (MRD) monitoring. This study aimed to characterize post-therapy immunophenotypic alterations in AMKL and to determine whether specific patterns of antigenic change exist between samples obtained at initial presentation (IP group) and those obtained at MRD-positive status after therapy (MRD group). This retrospective descriptive study included 110 patients diagnosed with AMKL at Hebei Yanda Lu Daopei Hospital between January 1, 2009 and December 31, 2024 (male:female = 57:53; 103 pediatric and 7 adult cases). Immunophenotypes at initial diagnosis and after treatment were analyzed by flow cytometry. The chi-square test was used to compare antigen expression between the IP and MRD groups. Flow cytometric immunophenotypes differed by at least three antigens (including CD33, CD61, and CD42b) between initial presentation and post-therapy samples. Compared with the IP group, the MRD group showed a significantly higher frequency of loss of megakaryocytic markers, including CD61 (11/109, 10.1% vs. 30/109, 27.5%; p < 0.05) and CD42b (6/106, 5.7% vs. 22/101, 21.8%; p < 0.05). Partial loss of CD13 expression was also more frequent in the MRD group (18/99, 18.2% vs. 2/83, 2.4%; p < 0.05). No significant differences were observed in the expression of progenitor-associated markers (CD34, CD117), myeloid markers (CD33, CD11b), or other antigens (HLA-DR, CD7, CD56, CD42a) between the two groups (p > 0.05). Lineage-specific markers MPO and CD22, the monocytic marker CD14, and lymphoid markers CD10 and CD5 were negative in both groups. In contrast, aberrant expression of cCD3 (2/89, 2.2%) and CD19 (3/85, 3.5%) was observed in a small subset of IP cases. Overall, 100 of 110 patients (90.9%) showed changes in at least one antigen after therapy. By lineage category, alterations were most frequent in megakaryocytic markers (CD61, CD42b, CD41a, CD42a; 64/110, 58.2%), followed by myeloid antigens (HLA-DR, CD33, CD13, CD11b; 54/108, 50.0%), progenitor-associated antigens (CD34, CD117; 53/110, 48.2%), and lymphoid antigens (CD7, CD56; 24/107, 22.4%). In addition, CD110 was consistently expressed in all 26 AMKL cases tested, whereas only 18% (9/50) of non-AMKL AML cases were CD110-positive (p < 0.05). Significant immunophenotypic differences, particularly involving CD61, CD42b, and CD13, exist between IP and MRD samples in AMKL. Antigenic shifts affecting megakaryocytic, myeloid, progenitor-associated, and lymphoid markers are common after chemotherapy. For MRD assessment, the use of more specific megakaryocytic markers such as CD110, together with comprehensive multiparameter flow cytometry panels, may improve detection accuracy.

The prognosis of acute megakaryoblastic leukemia (AMKL) is really dismal, which urges for development of novel treatment. Baicalein is one type of flavonoids extracted from Scutellaria baicalensis Georgi (Huang Qin). It inhibited cell proliferation and subcutaneous tumor formation of many tumor cell lines. However, whether baicalein possesses anti-AMKL activities has not been tested. We found that baicalein potently inhibited proliferation of multiple AMKL cells including CMK, CMY, Y10, 6133, and 6133 MPL/W515L due to apoptosis and cell cycle arrest at G1 phase. Unexpectedly, caspase inhibitor z-VAD-fmk did not restore cell proliferation. In contrast, ectopic expression of Cyclin D1 efficiently antagonized the inhibitory effect of baicalein. In addition, baicalein induced differentiation of 6133 MPL/W515L cells. Finally, baicalein promoted mice survival and reduced disease burden in a mouse model of AMKL. Baicalein possesses potent anti-AMKL activity in vitro and in vivo. Baicalein may be a potent reagent for AMKL therapy.

A CBFA2T3-GLIS2 fusion gene was identified in 31% of non–Down syndrome AMKL.

Key Points AMKL patients in 2000 to 2009 had better survival than those in 1989 to 1999, but outcomes for patients in 2000 to 2004 and 2005 to 2009 were comparable. Heterogeneous cytogenetic groups can be classified into good, intermediate, and poor risk on the basis of prognosis.

… Acute megakaryoblastic leukemia (AMKL) is a subtype of acute myeloid leukemia (AML) in … light on the etiology of AMKL and provide useful information for the tailoring of treatment. …

Acute megakaryoblastic leukemia (AMKL) is a rare hematological malignancy in adults but children. Alternative splicing (AS) has been shown to affect hematological cancer progression, making splicing factors promising targets. Our research aims to investigate the efficacy of the molecular glue degrader indisulam, which targets the splicing factor RNA binding motif protein 39 (RBM39) in AMKL models. Public drug sensitivity data analysis revealed that AMKL cell lines exhibited the highest sensitivity to indisulam compared with other tumor types. Then we confirmed that RBM39 depletion by indisulam treatment induced AMKL cell cycle arrest and apoptosis. In AMKL mouse model, indisulam treatment significantly reduced the leukemic burden and prolonged the lifetime of AMKL mice. Mechanically, integration of transcriptomic and proteomic analyses revealed that indisulam-mediated RBM39 degradation resulted in AS of the transcription factor zinc finger MYND-type containing 8 (ZMYND8), an AMKL cell growth regulator. Finally, the effectiveness of indisulam depended on DDB1- and Cul4- Associated Factor 15 (DCAF15) expression because knockout of DCAF15 rescued the indisulam-induced RBM39 degradation and mis-splicing of ZMYND8. Indisulam is a promising therapeutic candidate for AMKL and the RBM39-mediated ZMYND8 splicing plays an important role in promoting the development of AMKL.

Two girls, each less than 2 yr of age, developed acute megakaryoblastic leukemia (malignant myelosclerosis). Both presented with anemia, severe thrombocytopenia, and a low percentage of blasts in their peripheral blood. Their marrow showed marked reticulin fibrosis with an increase in blasts and immature megakaryocytes. The blasts stained negatively for myeloperoxidase and Sudan Black B, but showed acid phosphatase (ACP) and alpha-naphthyl acetate esterase (ANAE) activity inhibitable by sodium fluoride. They were identified as megakaryoblasts by the platelet peroxidase reaction. Cytogenetic studies showed multiple chromosomal abnormalities in both cases. Chemotherapy with vincristine, prednisone, and L-asparaginase was without effect, while daunorubicin and cytosine arabinoside induced a complete remission in one case. The second case responded to a combination of cytosine arabinoside, daunorubicin, and 6-thioguanine. This article documents that acute megakaryoblastic leukemia occurs in early childhood and describes its clinical, pathologic, and cytogenetic features. Previous reports of childhood “myelofibrosis” are reviewed, and their possible relationship with acute megakaryoblastic leukemia is discussed.

Acute megakaryoblastic leukemia (AMKL) remains a therapeutic challenge, with limited responsiveness to standard cytarabine-based regimens and frequent microenvironment-mediated resistance. Aberrant activation of the JAK-STAT signaling pathway has been implicated in AMKL pathogenesis but has not been fully exploited therapeutically in combination with cytarabine. We evaluated the antileukemic efficacy of combining a JAK inhibitor with cytarabine across multiple preclinical models: (i) AMKL cell lines (including CMK, CMY, MKPL1, UT7, MOLM16, Mo7e) assessing viability, apoptosis, and combination index; (ii) three-dimensional (3D) co-culture with mesenchymal cells (MSCs) modelling bone-marrow niche-mediated protection; and (iii) murine xenograft models of AMKL assessing leukemic burden and survival. In cell-line experiments, the JAK inhibitor plus cytarabine demonstrated marked synergy (combination index < 0.7) with significantly increased apoptosis (Annexin V+) and reduced proliferation compared to either agent alone. In the 3D MSC co-culture model, the microenvironment protected AMKL cells from cytarabine-induced death, but this protective effect was abrogated by JAK inhibition, restoring cytarabine sensitivity especially in MOLM16 and MKPL1 cells. In vivo, combination therapy significantly reduced leukemic burden (p < 0.05) and significantly prolonged median survival compared to cytarabine alone. Mechanistically, ruxolitinib suppressed phosphorylation of STAT3 and STAT5 and exerted a synergistic effect in combination with cytarabine; however, this inhibitory effect on phosphorylation was attenuated under the 3D co-culture condition. Our results provide robust preclinical evidence that combining JAK inhibition with cytarabine yields synergistic antileukemic effects in AMKL, including in a niche-protected context, and significantly improves in vivo outcomes. This data strongly supports the rationale for clinical evaluation of this combination in AMKL patients, especially those with JAK-STAT pathway activation. Akira Shimada, Shiho Aoki, Hiroko Hayakawa, Erico Jimbo, Narumi Omika, Kaito Furuya, Hideya Asai, Hiroki Yoshinari, Hitomi Niijima, Yuta Kawahara, Kentaro Ushijima, Masakazu Mimaki, Mitsuteru Hiwatari. Synergistic antileukemic activity of JAK inhibition combined with cytarabine in acute megakaryoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4467.

Forced polyploidization is an effective strategy for acute megakaryoblastic leukemia (AMKL) therapy and factors controlling polyploidization are potential targets for drug development. Although bone morphology protein 2-inducible kinase (BMP2K) has been implied to be a potential target for fasudil, a potent polyploidy-inducing compound, the function of BMP2K in megakaryopoiesis and AMKL remains unknown. This study aimed to investigate the role of BMP2K as a novel regulator in megakaryocyte polyploidization and differentiation and its implication in AMKL therapy. BMP2K upregulation was observed in human megakaryopoiesis and leukemia cells whereas BMP2K was downregulated in AMKL cells forced to undergo terminal differentiation. Functionally, BMP2K suppressed MLN8237-induced megakaryocytic differentiation in AMKL cells and dampened megakaryocyte differentiation in primary mouse fetal liver cells. Furthermore, BMP2K overexpression conferred resistance to multiple chemotherapy compounds in AMKL cells. Mechanistically, cyclin-dependent kinase 2 (CDK2) interacted with BMP2K and partially mediated its function. In transient MLN8237 and nocodazole challenge cell model, BMP2K reduced cell percentage of G2/M phase but increased G1 phase, suggesting a role of BMP2K antagonizing polyploidization and promoting mitosis by regulating cell cycle in megakaryopoiesis. BMP2K negatively regulates polyploidization and megakaryocyte differentiation by interacting CDK2 and promoting mitosis in megakaryopoiesis. BMP2K may serve as a potential target for improvement of AMKL therapy.

Therapy-related AML (t-AML) is one of the newly expanded disease entities in the 2008 WHO classification, accounting for 10-20% of all cases of AML, and its incidence is increasing worldwide because of improved survival rates following treatment for other primary cancers [1, 2]. Acute megakaryoblastic leukemia (AMKL) (M7) is the least common of the t-AML French-American-British (FAB) subtypes, and only two such cases have been reported to date [3, 4], neither of which was in Korea. AMKL accounts for about 7-10% of childhood AML cases (frequently associated with Down syndrome), but only about 1% of adult AML cases [5]. Here, we describe a rare case of therapy-related acute megakaryoblastic leukemia (t-AMKL) with chromosome 5 and 7 abnormalities that presented ten years after chemoradiotherapy in an elderly lung cancer patient.

… carcinoma who developed therapy related acute megakaryocytic … AMKL is a rare leukemia in adults and to the best of our knowledge this is the first reported case from India of therapy…

Acute megakaryoblastic leukemia (AMKL) is a rare subtype of acute myeloid leukemia accompanied by an aggressive clinical course and dismal prognosis. We herein report a case of AMKL preceded by mediastinal germ cell tumor that relapsed early after allogeneic hematopoietic stem cell transplantation with myeloablative conditioning but was successfully treated using salvage cord blood transplantation (CBT) with reduced-intensity conditioning. Although several serious complications developed, sustained remission with a favorable general condition was ultimately achieved. Although an optimal therapeutic strategy remains to be established, the graft-versus-leukemia effect of CBT may be promising, even for the treatment of refractory AMKL.

… However, in children with DS, therapy was often inappropriate … therapy due to infections had been reported in DS patients. … diagnosis of AMKL by immunophenotyping in some patients. …

Background: Acute megakaryocytic leukemia (AMKL) is a rare subtype of acute myeloid leukemia (AML) with a dismal outcome in children without Down syndrome. Refractory or relapsed disease accounts for treatment failure in most cases. Hematopoietic stem cell transplantation (HSCT) is recommended as post-remission therapy, although some patients have been cured with intensive chemotherapy alone. Genetic and genomic abnormalities are common in AMKL, but their prognostic significance is not known. In this study, we analyzed AMKL using high-throughput sequencing in addition to conventional morphology, immunophenotype, cytogenetic, and molecular (MICM) approaches. Methods: From February 2015 to April 2019, 19 cases of AMKL in non-Down syndrome patients were diagnosed according to conventional methods in our center. All patients, except one, were treated using a low-dose chemotherapy (LDC) regimen (cytarabine 10 mg/m2, subcutaneously every 12 h, 20 doses; mitoxantrone 5 mg/m2 days 1, 3 and 5, and G-CSF 5µ/kg subcutaneous, daily, 10 doses) for induction remission followed by four courses of intensive chemotherapy or hematopoietic stem cell transplantation (HSCT) as post-remission consolidation[1]. Patients were treated with consolidation chemotherapy if parents refused HSCT. High-throughput mutational sequencing of leukemia cells obtained at diagnosis was performed. The average sequencing depth was 500-1000× and analyses were performed using mGATK, SAMTools, SIFT, PolyPhen2, LRT, and MutatioinTaster methods. Results: The average age at diagnosis of AMKL of the nine boys and 10 girls was 19.7 months (7-53 months). Eighty-four percent of the cases were younger than 2 years of age. The 19 patients with AMKL represent 10% of cases diagnosed with AML during the study period. The median initial white blood cell (WBC) count was 13×109/L(2.38-126×109/L)and the average blasts at initial bone marrow (BM) was 54.5% (13-85%). In all cases of AMKL, more than 25% of cells were positive for CD41. Sixty-three percent of patients had recurrent fusion genes, including NUP98-KDM5A, HOXA11-AS/ANGPT1, CBFA2T3-GLIS2, KMT2A-MLLT3, RBM15-MKL1. Also, we identified PICALM-MLL10, TNIP1-CSF1R, NUP98-TAF3, and CBFA2T3-GLIS1 fusion genes which had not been previously reported in AMKL. EVI-1 expression was evaluated in all cases and was overexpressed in two cases. Forty-seven percent of patients showed at least single-gene mutations, including JAK2, MPL, KRAS, NRAS, TP53, NTRK3, MYO16, PDGFB, FLT3, and others. The response rate after remission induction I (IND-I) were 84.2% with 63.1% (12/19) attaining complete remission (CR) and 21.1% (4/19) partial remission (PR). After IND-II, the CR, PR, and no response (NR) rates was 68.4%, 10.5%, and 21.1%, respectively. Four patients (21.1%) were refractory to induction chemotherapy. Seven patients (36.8%) relapsed, three during consolidation chemotherapy courses, and four after transplantation (Table 1). Currently, 75% (6/8) patients who received chemotherapy only for consolidation were alive (median follow-up time 27 months). Eleven patients underwent allo-HSCT, and 8 patients are alive, including 6 cases living without evidence of disease. Four patients relapsed after allo-HSCT, and two of them have died. One additional patient died of transplantation related mortality. The 4-year OS, RFS, and EFS in this cohort were 62.4%±13.9%, 54.1±13.0% and 40.5±11.5%, respectively (Figure 1).Conclusion: Non-Down syndrome AMKL is genetically heterogeneous with recurrent and new fusion genes. Patients treated with LDC for induction followed by intensive chemotherapy or HSCT for consolidation have outcome comparable to those treated with intensive induction regimens. New treatment strategies are needed to improve the outcome of pediatric AMKL. Figure 1 No relevant conflicts of interest to declare.

Bcakground: Pediatric acute megakaryoblastic leukemia (AMKL) without Down syndrome (DS) is a genetically heterogenous myeloid malignancy and with dismal prognosis. Refractory and relapse remains a major challenge. Given to the young age distribution of AMKL and high frequency of abandonment in middle-income countries, we conducted a multicenter clinical trial (ChiCTR1800015875) in aims to lower the intensity of induction while without compromise the remission rate and survival. Methods: From June 2018 to December 2022, there were consecutively 43 cases with de novo non-DS AMKL, which accounted for 7.6% cases of acute myeloid leukemia (AML) during the same period, enrolled in this trial. All the patients received at least one cycle of low-dose induction with HAG regimen (homoharringtonine 1 mg/m 2, intravenous daily, days 1-7; cytarabine 10 mg/m 2, subcutaneously every 12 hours, 20 doses, and G-CSF 5µ/kg subcutaneous, daily, 10 doses) followed by 3 to 4 courses of intensive chemotherapy or HSCT as post-remission consolidation. Besides conventional molecule testing, RNA-sequencing and whole exon sequencing (WES) were performed as well to reveal underlying genetic landscape of this type of disease. Results: The median age of the 43 patients at diagnosis was 18.5 (range 4-114) months. The median while blood cell (WBC) counts and platelet at diagnosis were 17.2×10 9/L (range 1.8-105.7 ×10 9/L) and 36.5×10 9/L (range 4-472 ×10 9/L), respectively. Among them, 39.5% of cases exhibited hepatosplenomegaly. A diversity of genetic fusions and mutations were uncovered. The recurrent fusions in this cohort include CBFA2T3-GLIS2 (16.3%), MLLr (11.6%), NUP98-(9.3%), RBM15-MKL1 (7.0%), HOX fusions (7.0%) and PICALM-MLLT10 (4.7%). Other non-recurrent fusions accounted for 18.6% (Figure 1A). The common mutations detected in our pediatric AMKL were JAK2, NRAS, MPL, BCOR, CTCF, KRAS and PTPN11. Regarding treatment response, 20 of 43 cases (46.5%) attained complete remission (CR) or complete remission with incomplete blood cell recovery (CRi) after one cycle of induction. Among the 20 cases, 9 of them got minimal residual disease (MRD) negative by flow cytometry. Ten patients (23.2%) achieved partial remission (PR) while 13 patients (30.2%) showed no response (NR) to treatment. Thirty-one patients continued with another cycle of the same regimen and 21 of the 28 cases who were available for evaluation (75.0%) attained CR/CRi. Disease relapse was observed in 16/43 (37.2%) cases, with 7/43 (16.2%) patients relapsed after transplantation. The 3-year overall survival (OS) and event-free survival (EFS) were 49.6±8.2% and 29.5±7.1%, respectively (Figure 1B). In total, more than half of patients (22/43, 51.5%) underwent HSCT. The 3-year OS of transplant group and chemotherapy group were 57.9±11.7% versus 39.5±11.2%, P=0.036. As genetic characteristics often predict treatment response and prognosis, we wonder which subgroup could benefit from the reduced intensive induction. We further compared the features of patients who got CR/CRi after induction I with those achieved PR/NR. Interestingly, we found more patients with adverse fusions in PR/NR group, such as CBFA2T3-GLIS2 (26.0% vs. 5.0%), NUP98- (17.4% vs. 0%), MLLs (13.0% vs. 10.0%), and RBM15-MKL1 (8.7% vs. 5.0%); while other non-recurrent fusions were more common in CR/CRi group (4.3% vs. 35.0%). Two thirds of patients (67.4%) experienced refractory or relapse and almost half of them harbored adverse fusions or mutations such as CBFA2T3-GLIS2, MLLr, NUP98- fusions, NRAS and PTPN11. On the other hand, 14 patients without refractory or relapse had genetic features with more JAK2 and MPL mutations. No treatment-related mortality (TRM) occurred during induction. Only one patient with KRAS mutation died of infection after consolidation III. Conclusion: Insight into the genetic and molecular landscape improved our understanding of pediatric AMKL. Distinct molecular features can serve as a tool to tailor the therapy. Though treatment still lags behind and novel therapy is urgent for the adverse subgroups, our low-dose induction with HAG regimen could benefit for a subgroup with non-recurrent fusions, which showed efficiency while is tolerable for the young age group. Based on our results, we provide an induction option for these AMKL patients, especially for those in the middle-income countries.

… and consolidation therapies. Therefore, no reduction in the dosage of chemotherapy for … The treatment results for children without Down syndrome who have AMKL have been poor 10, …

… -AMKL who was cured with non-myeloablative chemotherapy. A 19-month-old boy with Down syndrome, who had transient leukemia as a newborn, developed DS-AMKL (… consolidation …

RUNX1 (AML1) encodes the core binding factor α subunit of a heterodimeric transcription factor complex which plays critical roles in normal hematopoiesis. Translocations or down-regulation of RUNX1 have been linked to favorable clinical outcomes in acute leukemias, suggesting that RUNX1 may also play critical roles in chemotherapy responses in acute leukemias; however, the molecular mechanisms remain unclear. The median level of RUNX1b transcripts in Down syndrome (DS) children with acute megakaryocytic leukemia (AMkL) were 4.4-fold (P &lt; .001) lower than that in non-DS AMkL cases. Short hairpin RNA knockdown of RUNX1 in a non-DS AMkL cell line, Meg-01, resulted in significantly increased sensitivity to cytosine arabinoside, accompanied by significantly decreased expression of PIK3CD, which encodes the δ catalytic subunit of the survival kinase, phosphoinositide 3 (PI3)–kinase. Transcriptional regulation of PIK3CD by RUNX1 was further confirmed by chromatin immunoprecipitation and promoter reporter gene assays. Further, a PI3-kinase inhibitor, LY294002, and cytosine arabinoside synergized in antileukemia effects on Meg-01 and primary pediatric AMkL cells. Our results suggest that RUNX1 may play a critical role in chemotherapy response in AMkL by regulating the PI3-kinase/Akt pathway. Thus, the treatment of AMkL may be improved by integrating PI3-kinase or Akt inhibitors into the chemotherapy of this disease.

Children with Down syndrome (DS) with acute megakaryocytic leukemia (AMkL) have very high survival rates compared with non-DS AMkL patients. Somatic mutations identified in the X-linked transcription factor gene, GATA1, in essentially all DS AMkL cases result in the synthesis of a shorter (40 kDa) protein (GATA1s) with altered transactivation activity and may lead to altered expression of GATA1 target genes. Using the Affymetrix U133A microarray chip, we identified 551 differentially expressed genes between DS and non-DS AMkL samples. Transcripts for the bone marrow stromal-cell antigen 2 (BST2) gene, encoding a transmembrane glycoprotein potentially involved in interactions between leukemia cells and bone marrow stromal cells, were 7.3-fold higher (validated by real-time polymerase chain reaction) in the non-DS compared with the DS group. Additional studies confirmed GATA1 protein binding and transactivation of the BST2 promoter; however, stimulation of BST2 promoter activity by GATA1s was substantially reduced compared with the full-length GATA1. CMK sublines, transfected with the BST2 cDNA and incubated with HS-5 bone marrow stromal cells, exhibited up to 1.7-fold reduced cytosine arabinoside (ara-C)-induced apoptosis, compared with mock-transfected cells. Our results demonstrate that genes that account for differences in survival between DS and non-DS AMkL cases may be identified by microarray analysis and that differential gene expression may reflect relative transactivation capacities of the GATA1s and full-length GATA1 proteins.

… induction and tolerated chemotherapy well. The third dose of consolidation therapy was not … Although such cases are rare, our case illustrates that the treatment regimen for AMKL …

BACKGROUND Acute megakaryoblastic leukemia (AMKL) is a biologically heterogeneous subtype of acute myeloid leukemia that originates from megakaryocytes. Patients with AMKL with non-Down syndrome (DS) had a poorer prognosis. However, clear prognostic indicators and treatment recommendations for this subgroup remain controversial. PATIENTS AND METHODS Herein, we performed a retrospective study on 40 patients (age ≤ 18 years) with non-Down syndrome AMKL at our institution. We assessed the effect of different prognostic factors, such as their cytogenetic abnormalities, early treatment response, and the role of hematopoietic stem cell transplantation (HSCT) as post-remission treatment on the outcomes. RESULTS The complete remission (CR) rate of the patients was 57.9% and 81.1%, respectively, at the end of induction therapy 1 and 2. The overall survival (OS) and event-free survival rates at 2 years were 41% ± 13% and 41% ± 10%, respectively. An analysis of the cytogenetic features showed that patients with +21 or hyperdiploid (> 50 chromosomes) had significantly better OS than those in other cytogenetic subgroups (Plog-rank = .048 and Plog-rank = .040, respectively). Besides cytogenetics, an excellent early treatment response (CR and minimal residual disease < 1% after induction therapy 1) also provided a significant survival benefit in univariate analysis in our study. However, multivariate analysis indicated that allogeneic HSCT was the only independent prognostic marker (relative risk, 11.192; 95% confidence interval, 2.045-61.241; P = .005 for OS and relative risk, 5.400; 95% confidence interval, 1.635-17.832; P = .006 for event-free survival, respectively). CONCLUSION AMKL in patients with non-Down syndrome has a poor outcome. With poor OS but CR rates comparable with other acute myeloid leukemia subtypes, allogenic HSCT may be a better option for post-remission therapy than conventional chemotherapy, especially for those having a poor response to induction therapy.

Acute erythroid leukemia (FAB-M6) and acute megakaryoblastic leukemia (FAB-M7) exhibit closely related properties in cells regarding morphology and the gene expression profile. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered the mainstay of the treatment for both subtypes of leukemia due to their refractoriness to chemotherapy and high rates of relapse, it remains unclear whether allo-HSCT is curative in such cases due to their scarcity. We retrospectively examined the impact of allo-HSCT in 382 patients with M6 and 108 patients with M7 using nationwide HSCT data and found the overall survival (OS) and relapse rates of the M6 patients to be significantly better than those of the M7 patients after adjusting for confounding factors and statistically comparable with those of the patients with M0/M1/M2/M4/M5 disease. Consequently, the factors of age, gender, performance status, karyotype, disease status at HSCT and development of graft-vs.-host disease predicted the OS for the M6 patients, while the performance status and disease status at HSCT were predictive of the OS for the M7 patients. These findings substantiate the importance of distinguishing between M6 and M7 in the HSCT setting and suggest that unknown mechanisms influence the HSCT outcomes of these closely related subtypes of leukemia.

Pediatric non-Down-syndrome acute megakaryoblastic leukemia (non-DS-AMKL) is a heterogeneous subtype of leukemia that has historically been associated with poor prognosis. Until the advent of large-scale genomic sequencing, the management of patients with non-DS-AMKL was very difficult due to the absence of reliable biological prognostic markers. The sequencing of large cohort of pediatric non-DS-AMKL samples led to the discovery of novel genetic aberrations, including high-frequency fusions, such as CBFA2T3-GLIS2 and NUP98-KDM5 A, as well as less frequent aberrations, such as HOX rearrangements. These new insights into the genetic landscape of pediatric non-DS-AMKL has allowed refining the risk-group stratification, leading to important changes in the prognostic scenario of these patients. This review summarizes the most important molecular pathogenic mechanisms of pediatric non-DS-AMKL. A critical discussion on how novel genetic abnormalities have refined the risk profile assessment and changed the management of these patients in clinical practice is also provided.

CBFA2T3-GLIS2 is the most frequent chimeric oncogene identified to date in non–Down syndrome acute megakaryocytic leukemia (AMKL), which is associated with extremely poor clinical outcome. The presence of this fusion gene is associated with resistance to high-intensity chemotherapy, including hematopoietic stem cell transplantation (HSCT), and a high cumulative incidence of relapse frequency. The clinical features and clinical effects of China Children’s Leukemia Group–acute myeloid leukemia (AML) 2015/2019 regimens and haploidentical HSCT (haplo-HSCT) for treatment of 6 children harboring the CBFA2T3-GLIS2 fusion gene between January 2019 and December 2021 were retrospectively analyzed. The 6 patients included 4 boys and 2 girls with a median disease-onset age of 19.5 months (range: 6–67 mo) who were diagnosed with AMKL. Flow cytometry demonstrated CD41a, CD42b, and CD56 expression and lack of HLA-DR expression in all 6 patients. All the children were negative for common leukemia fusion genes by reverse transcription polymerase chain reaction, but positive for the CBFA2T3-GLIS2 fusion gene by next-generation sequencing and RNA sequencing. All patients received chemotherapy according to China Children’s Leukemia Group–AML 2015/2019 regimens, and 4 achieved complete remission. Four children underwent haplo-HSCT with posttransplant cyclophosphamide-based conditioning; 3 had minimal residual disease negative (minimal residual disease <0.1%) confirmed by flow cytometry at the end of the follow-up, with the remaining patient experiencing relapse at 12 months after transplantation. Transcriptome RNA sequencing is required for the detection of the CBFA2T3-GLIS2 fusion gene and for proper risk-based allocation of pediatric patients with AML in future clinical strategies. Haplo-HSCT with posttransplant cyclophosphamide–based conditioning may improve survival in children with AMKL harboring the fusion gene.

… of HSCT for AMKL patients could not be demonstrated,13 these results indicated that HSCT at first CR should be considered in CBFA2T3-GLIS2-positive patients to avoid relapse. …

Non-Down’s syndrome acute megakaryocytic leukemia (non-DS-AMKL) is a subtype of childhood acute myeloid leukemia (AML), whose prognosis, prognostic factors and treatment recommendations have not yet to be defined in children. We conducted a retrospective study with 65 newly diagnosed non-DS-AMKL children from August 2003 to June 2020 to investigate the clinical impact of factors and clinical outcome. Among all 65 patients, 47 of them were treated at our center who received three different regimens due to time point of admission (CAMS-another, CAMS-2009 and CAMS-2016 protocol), and the efficacy were compared. Patients with newly diagnosed non-DS-AMKL accounted for 7.4% of pediatric AML cases. The median age of the patients was 18 months at diagnosis, and over 90% of them were under three-years-old. The overall survival (OS) rates were 33.3% ± 1.7%, 66.7% ± 24.4% and 74.2% ± 4.0% for three groups (CAMS-another, CAMS-2009 and CAMS-2016 regimen), respectively. In CAMS-2016 group, the complete remission (CR) rate after induction was 67.7% (21/31), while the total CR rate after all phases of chemotherapy was 80.6% (25/31). The 2-year survival probability did not significantly improve in patients underwent HSCT when compared with non-HSCT group (75.0% ± 4.7% vs. 73.9% ± 4.6%, p=0.680). Those who had a “dry tap” during BM aspiration at admission had significantly worse OS than those without “dry tap” (33.3% ± 8.6% vs. 84.0% ± 3.6%, p=0.006). Moreover, the results also revealed that patients with CD34+ had significantly lower OS (50.0% ± 6.7% vs. 89.5% ± 3.5%, p=0.021), whereas patients with CD36+ had significantly higher OS than those who were negative (85.0% ± 4.0% vs. 54.5% ± 6.6%, p=0.048). In conclusion, intensive chemotherapy resulted in improved prognosis of non-DS-AMKL children and subclassification may base on “dry tap” and immunophenotypic. Although some progress has been made, outcomes of non-DS-AMKL children remain unsatisfactory, especially in HSCT group, when compared with other AML types.

Acute megakaryoblastic leukaemia (AMKL) is associated with poor prognosis. Limited information is available on its cytogenetics, molecular genetics and clinical outcome. We performed genetic analyses, evaluated prognostic factors and the value of allogeneic haematopoietic stem cell transplantation (allo‐HSCT) in a homogenous adult AMKL patient cohort. We retrospectively analysed 38 adult patients with AMKL (median age: 58 years, range: 21–80). Most received intensive treatment in AML Cooperative Group (AMLCG) trials between 2001 and 2016. Cytogenetic data showed an accumulation of adverse risk markers according to ELN 2017 and an unexpected high frequency of structural aberrations on chromosome arm 1q (33%). Most frequently, mutations occurred in TET2 (23%), TP53 (23%), JAK2 (19%), PTPN11 (19%) and RUNX1 (15%). Complete remission rate in 33 patients receiving intensive chemotherapy was 33% and median overall survival (OS) was 33 weeks (95% CI: 21–45). Patients undergoing allo‐HSCT (n = 14) had a superior median OS (68 weeks; 95% CI: 11–126) and relapse‐free survival (RFS) of 27 weeks (95% CI: 4–50), although cumulative incidence of relapse after allo‐HSCT was high (62%). The prognosis of AMKL is determined by adverse genetic risk factors and therapy resistance. So far allo‐HSCT is the only potentially curative treatment option in this dismal AML subgroup.

Acute megakaryoblastic leukaemia (AMKL) is a rare subtype of acute myeloid leukaemia (AML) that accounts for 1% of adult AML cases. AMKL is a more common subtype of childhood or infant AML, that occurs especially in children with Down syndrome. The cytogenetic abnormality t (1;22)(p13 3;q13 1) results in the fusion of two genes, namely the RNA-binding motif protein-15 (RBM15) and megakaryoblastic leukaemia-1 (MKL1). AMKL with t(1;22) (p13 3;q13 1)/RBM15-MKL1 has been reported only in infants or young children (age < 3 years), with most cases occurring in the first 6 months of life (median patient age 4 months). Here, we report the first documented adult patient with AMKL carrying t(1,22)(p13 3;q13 1)/RBM15MKL1 following treatment for a non-mediastinal germ cell tumour (GCT). A 31-year-old man was diagnosed with a non-mediastinal GCT with a bulky retroperitoneal mass lesion. After receiving four cycles of bleomycin, etoposide and cisplatin (BEP) therapy followed by surgical resection of the residual mass lesion, the patient achieved complete remission. Five months after the completion of BEP therapy, a follow-up blood test demonstrated thrombocytopenia with a platelet count of 62 9 10/l. The white blood cell count was 5 1 9 10/l without the appearance of blastic cells, while the haemoglobin level was 10 4 g/dl. The patient was subsequently referred to our department for thrombocytopenia. A bone marrow (BM) examination indicated a slightly hypocellular marrow with proliferation of blastic cells Fig 1. Flow cytometry analysis revealed that the blastic cells were positive for CD34, CD117, CD13, CD41a and CD61. The BM biopsy revealed an increase in tumour cells positive for CD41 (Fig 1) however, they were negative for GCT markers, including AE1/3, OCT3/4 and SALL4. Based on these findings, the patient was diagnosed with AMKL. Cytogenetic analysis revealed t(1;22)(p13 3;q13 1) present in four of 20 metaphase cells, while the cells tested negative for isochromosome 12p [i(12p)], a clonal marker common in GCTs. The RBM15-MKL1 fusion gene was detected in a BM sample by reverse transcription polymerase chain reaction (RT-PCR). Thus, the patient was diagnosed with AMKL with t

Advancements in genomic profiling have significantly improved the classification and treatment strategies for acute myeloid leukemia (AML). However, widely utilized molecular diagnostic techniques, including targeted gene panels, are often insufficient for detecting complex structural variants, cryptic fusions, and poorly characterized driver mutations. Here, we present the case of a 15‐month‐old female with pediatric acute megakaryoblastic leukemia (AMKL) who exhibited an atypical clinical presentation. Initial imaging revealed expansile lesions in the pelvic bones and vertebral bodies, prompting suspicion of malignancy. Conventional diagnostics, including immunohistochemistry and targeted sequencing, failed to identify a definitive oncogenic driver. Whole genome sequencing (WGS) identified a CBFA2T3::GLIS2 fusion, leading to a revised AMKL diagnosis with a RAM immunophenotype. The patient underwent induction chemotherapy with cytarabine and mitoxantrone, followed by salvage therapy with venetoclax and azacitidine, resulting in morphologic remission. Subsequent haploidentical hematopoietic stem cell transplantation achieved remission, with ongoing hematologic recovery. This case underscores the limitations of conventional molecular assays in detecting cryptic fusions and highlights the critical role of comprehensive genomic profiling in refining subclassification and optimizing therapeutic strategies in pediatric AML.

… hSCT in first complete remission is under discussion particularly in view of the potentially severe … , as was the case in our patient, allo-hSCT has the potential to induce long-term survival …

Introduction It was first reported that germ cell tumor patients suffer from hematologic malignancies 37 years ago. Since then, the number of relevant reports has increased each year, with most cases being mediastinal germ cell tumor. Theories have been proposed to explain this phenomenon, including a shared origin of progenitor cells, the effects of treatment, and independent development. However, up to now, no widely accepted explanation exists. The case with acute megakaryoblastic leukemia and intracranial germ cell tumor has never been reported before and the association is far less known. Methods We used whole exome sequencing and gene mutation analysis to study the relationship between intracranial germ cell tumor and acute megakaryoblastic leukemia of our patient. Results We report a patient who developed acute megakaryoblastic leukemia after treatment for an intracranial germ cell tumor. Through whole exome sequencing and gene mutation analysis, we identified that both tumors shared the same mutation genes and mutation sites, suggesting they originated from the same progenitor cells and differentiated in the later stage. Discussion Our findings provide the first evidence supporting the theory that acute megakaryoblastic leukemia and intracranial germ cell tumor has the same progenitor cells.

In the context of precision medicine, assessment of minimal residual disease (MRD) has been used in acute myeloid leukemia (AML) to direct individual treatment programs, including allogeneic stem cell transplantation in patients at high-risk of relapse. One of the limits of this approach has been in the past the paucity of AML markers suitable for MRD assessment. Recently, the number of biomarkers has increased, due to the identification of highly specific leukemia-associated immunophenotypes by multicolor flow-cytometry, and of rare mutated gene sequences by digital droplet PCR, or next-generation sequencing (NGS). In addition, NGS allowed unraveling of clonal heterogeneity, present in AML at initial diagnosis or developing during treatment, which influences reliability of specific biomarkers, that may be unstable during the disease course. The technological advances have increased the application of MRD-based strategies to a significantly higher number of AML patients, and the information deriving from MRD assessment has been used to design individual post-remission protocols and pre-emptive treatments in patients with sub-clinical relapse. This led to the definition of MRD-negative complete remission as outcome definition in the recently published European Leukemianet MRD guidelines. In this review, we summarized the principles of modern technologies and their clinical applications for MRD detection in AML patients, according to the specific leukemic markers.

… reaction (qPCR or dPCR) for MRD monitoring in molecularly defined subgroups, that is, … AML (containing translocations involving RUNX1-RUNX1T1 or CBFB-MYH11). MRD monitoring …

In recent years, major advances in the understanding of acute myeloid leukemia (AML) pathogenesis, together with technological progress, have led us into a new era in the diagnosis and follow-up of patients with AML. A combination of immunophenotyping, cytogenetic and molecular studies are required for AML diagnosis, including the use of next-generation sequencing (NGS) gene panels to screen all genetic alterations with diagnostic, prognostic and/or therapeutic value. Regarding AML monitoring, multiparametric flow cytometry and quantitative PCR/RT-PCR are currently the most implemented methodologies for measurable residual disease (MRD) evaluation. Given the limitations of these techniques, there is an urgent need to incorporate new tools for MRD monitoring, such as NGS and digital PCR. This review aims to provide an overview of the different technologies used for AML diagnosis and MRD monitoring and to highlight the limitations and challenges of current versus emerging tools.

Measurable residual disease (MRD) assessment in acute myeloid leukemia (AML) has an established role in disease prognostication, particularly in guiding decisions for hematopoietic cell transplantation in first remission. Serial MRD assessment is now routinely recommended in the evaluation of treatment response and monitoring in AML by the European LeukemiaNet. The key question remains, however, if MRD in AML is clinically actionable or “does MRD merely portend fate”? With a series of new drug approvals since 2017, we now have more targeted and less toxic therapeutic options for the potential application of MRD-directed therapy. Recent approval of NPM1 MRD as a regulatory endpoint is also foreseen to drastically transform the clinical trial landscape such as biomarker-driven adaptive design. In this article, we will review (1) the emerging molecular MRD markers (such as non-DTA mutations, IDH1/2, and FLT3-ITD); (2) the impact of novel therapeutics on MRD endpoints; and (3) how MRD might be used as a predictive biomarker to guide therapy in AML beyond its prognostic role, which is the focus of two large collaborative trials: AMLM26 INTERCEPT (ACTRN12621000439842) and MyeloMATCH (NCT05564390).

Simple Summary Acute myeloid leukemia is the most common type of leukemia in adults. It is frequently associated with a limited response to conventional therapies that have a high recurrence and mortality rate in the elderly population. Even patients with clinical remission after initial treatment eventually relapse due to measurable residual disease. An earlier and more accurate diagnosis of this condition, using tools with higher sensitivity and specificity, would allow for a more reliable prognosis of patients, leading to more favorable outcomes. Abstract Acute myeloid leukemia (AML) comprises a group of hematologic neoplasms characterized by abnormal differentiation and proliferation of myeloid progenitor cells. AML is associated with poor outcome due to the lack of efficient therapies and early diagnostic tools. The current gold standard diagnostic tools are based on bone marrow biopsy. These biopsies, apart from being very invasive, painful, and costly, have low sensitivity. Despite the progress uncovering the molecular pathogenesis of AML, the development of novel detection strategies is still poorly explored. This is particularly important for patients that check the criteria for complete remission after treatment, since they can relapse through the persistence of some leukemic stem cells. This condition, recently named as measurable residual disease (MRD), has severe consequences for disease progression. Hence, an early and accurate diagnosis of MRD would allow an appropriate therapy to be tailored, improving a patient’s prognosis. Many novel techniques with high potential in disease prevention and early detection are being explored. Among them, microfluidics has flourished in recent years due to its ability at processing complex samples as well as its demonstrated capacity to isolate rare cells from biological fluids. In parallel, surface-enhanced Raman scattering (SERS) spectroscopy has shown outstanding sensitivity and capability for multiplex quantitative detection of disease biomarkers. Together, these technologies can allow early and cost-effective disease detection as well as contribute to monitoring the efficiency of treatments. In this review, we aim to provide a comprehensive overview of AML disease, the conventional techniques currently used for its diagnosis, classification (recently updated in September 2022), and treatment selection, and we also aim to present how novel technologies can be applied to improve the detection and monitoring of MRD.

In acute myeloid leukemia (AML) many patients experience relapse, despite the achievement of morphological complete remission; therefore, conventional morphologic criteria are currently considered inadequate for assessing the quality of the response after treatment. Quantification of measurable residual disease (MRD) has been established as a strong prognostic marker in AML and patients that test MRD negative have lower relapse rates and better survival than those who test positive. Different techniques, varying in their sensitivity and applicability to patients, are available for the measurement of MRD and their use as a guide for selecting the most optimal post-remission therapy is an area of active investigation. Although still controversial, MRD prognostic value promises to support drug development serving as a surrogate biomarker, potentially useful for accelerating the regulatory approval of new agents. In this review, we will critically examine the methods used to detect MRD and its potential role as a study endpoint.

In recent years there have been major advances in the use of molecular diagnostic and monitoring techniques for patients with acute myeloid leukaemia (AML). Coupled with the simultaneous explosion of new therapeutic agents, this has sown the seeds for significant improvements to treatment algorithms. Here we show, using a selection of real‐life examples, how molecular monitoring can be used to refine clinical decision‐making and to personalise treatment in patients with AML with nucleophosmin (NPM1) mutations, core binding factor translocations and other fusion genes. For each case we review the established evidence base and provide practical recommendations where evidence is lacking or conflicting. Finally, we review important technical considerations that clinicians should be aware of in order to safely exploit these technologies as they undergo widespread implementation.

Background AMKL without DS is a rare but aggressive hematological malignant disease in children, and it is associated with inferior outcomes. Several researchers have regarded pediatric AMKL without DS as high-risk or at least intermediate-risk AML and proposed that upfront allogenic hematopoietic stem cell transplantation (HSCT) in first complete remission might improve long-term survival. Patients and method We conducted a retrospective study with twenty-five pediatric (< 14 years old) AMKL patients without DS who underwent haploidentical HSCT in the Peking University Institute of Hematology, Peking University People’s Hospital from July 2016 to July 2021. The diagnostic criteria of AMKL without DS were adapted from the FAB and WHO: ≥ 20% blasts in the bone marrow, and those blasts expressed at least one or more of the platelet glycoproteins: CD41, CD61, or CD42. AMKL with DS and therapy related AML was excluded. Children without a suitable closely HLA-matched related or unrelated donor (donors with more than nine out of 10 matching HLA-A, HLA-B, HLA-C, HLA-DR, and HLA-DQ loci), were eligible to receive haploidentical HSCT. Definition was adapted from international cooperation group. All statistical tests were conducted with SPSS v.24 and R v.3.6.3. Results The 2-year OS was 54.5 ± 10.3%, and the EFS was 50.9 ± 10.2% in pediatric AMKL without DS undergoing haplo-HSCT. Statistically significantly better EFS was observed in patients with trisomy 19 than in patients without trisomy 19 (80 ± 12.6% and 33.3 ± 12.2%, respectively, P = 0.045), and OS was better in patients with trisomy 19 but with no statistical significance (P = 0.114). MRD negative pre-HSCT patients showed a better OS and EFS than those who were positive (P < 0.001 and P = 0.003, respectively). Eleven patients relapsed post HSCT. The median time to relapse post HSCT was 2.1 months (range: 1.0–14.4 months). The 2-year cumulative incidence of relapse (CIR) was 46.1 ± 11.6%. One patient developed bronchiolitis obliterans and respiratory failure and died at d + 98 post HSCT. Conclusion AMKL without DS is a rare but aggressive hematological malignant disease in children, and it is associated with inferior outcomes. Trisomy 19 and MRD negative pre-HSCT might contribute to a better EFS and OS. Our TRM was low, haplo-HSCT might be an option for high-risk AMKL without DS.

Despite advances in acute myeloid leukemia (AML) treatment, significant unmet medical needs remain. Surrogate end points for overall survival can accelerate the approval of novel therapies. Measurable residual disease (MRD) is a promising surrogate end point candidate, providing a sensitive and quantitative assessment of disease burden. Numerous studies have demonstrated that negative MRD status—across diverse methodologies, assessment timepoints and thresholds, patient subgroups, and clinical settings—independently predicts improved survival. Although MRD can inform therapeutic decisions at the patient level, its formal integration as a primary surrogate end point in regulatory frameworks for clinical trials requires rigorous validation. MRD Partnership and Alliance in AML Clinical Treatment (MPAACT) is a research consortium among industry and academic leaders. MPAACT actively engages with regulatory agencies, health technology assessment bodies, technology vendors, and patient groups to establish a pathway for validating MRD as a surrogate end point in AML clinical trials. For the current article, the authors reviewed the status of MRD assessment, its use in recent clinical trials, current MRD assessment methodologies, standardization, regulatory guidance, statistical approaches, and patient access considerations necessary for MRD to become a surrogate clinical trial end point. The extensive collaboration between MPAACT, global industry, and academic partners—including data sharing and resource integration—underscores the collective commitment to advancing AML therapies. Establishing MRD as a surrogate end point could accelerate the development and approval of innovative treatments, ultimately improving patient outcomes.

No standard salvage regimen exists for relapsed/refractory (R/R) pediatric AML. In this prospective, multicenter Phase II trial, 101 evaluable patients (.

Pediatric acute myeloid leukemia (AML) represents 15%–20% of all pediatric acute leukemias. Survival rates have increased over the past few decades to ~70%, due to improved supportive care, optimized risk stratification and intensified chemotherapy. In most children, AML presents as a de novo entity, but in a minority, it is a secondary malignancy. The diagnostic classification of pediatric AML includes a combination of morphology, cytochemistry, immunophenotyping and molecular genetics. Outcome is mainly dependent on the initial response to treatment and molecular and cytogenetic aberrations. Treatment consists of a combination of intensive anthracycline- and cytarabine-containing chemotherapy and stem cell transplantation in selected genetic high-risk cases or slow responders. In general, ~30% of all pediatric AML patients will suffer from relapse, whereas 5%–10% of the patients will die due to disease complications or the side-effects of the treatment. Targeted therapy may enhance anti-leukemic efficacy and minimize treatment-related morbidity and mortality, but requires detailed knowledge of the genetic abnormalities and aberrant pathways involved in leukemogenesis. These efforts towards future personalized therapy in a rare disease, such as pediatric AML, require intensive international collaboration in order to enhance the survival rates of pediatric AML, while aiming to reduce long-term toxicity.

… results, decitabine has shown to be more effective than 5-azacitidine. Decitabine should be … To better characterize DS-like AMKL, we analyzed clinical and hematological characteristics…

… acute megakaryoblastic leukemia (AMKL) harboring KMT2A-… biopsy and received another course of decitabine and HAG (… achieved remission after use of decitabine and interferon α2b. …

Acute myeloid leukemia (AML) is a heterogeneous disease regarding morphology, immunophenotyping, genetic abnormalities, and clinical behavior. The overall survival rate of pediatric AML is 60% to 70%, and has not significantly improved over the past two decades. Children with Down syndrome (DS) are at risk of developing acute megakaryoblastic leukemia (AMKL), which can be preceded by a transient myeloproliferative disorder during the neonatal period. Intensification of current treatment protocols is not feasible due to already high treatment‐related morbidity and mortality. Instead, more targeted therapies with less severe side effects are highly needed.

Acute megakaryoblastic leukemia (AMKL) is a heterogeneous form of acute myeloid leukemia (AML) and is significantly more common in children than in adults. In non-Down syndrome children with AMKL, inv(16)(p13q24)/CBFA2T3::GLIS2 is the most frequent genetic aberration. Pediatric CBFA2T3::GLIS2-positive AMKL is strongly associated with a poor prognosis and a high cumulative incidence of relapse. One of the key laboratory signs of CBFA2T3::GLIS2-positive AMKL is the RAM immunophenotype, which includes dim to negative CD45 and CD38 expression, extremely bright CD56 and a lack of HLA-DR on leukemic cells. This immunophenotype looks very similar to that of solid tumor bone marrow (BM) infiltration. For this reason, in cases of isolated extramedullary involvement of CBFA2T3::GLIS2-positive AMKL, excluding solid tumors may be challenging. The differential diagnosis between extramedullary AMKL relapse and secondary tumors is especially difficult. We report a case of a 3.5-year-old girl with isolated extramedullary CBFA2T3::GLIS2-positive AMKL relapse, which was misdiagnosed as secondary Ewing sarcoma. The morphological differential diagnosis between Ewing sarcoma and AMKL presents significant challenges owing to their overlapping histological features (small round blue cell morphology and similar growth patterns). The tumor cells immunophenotype was completely mirrored that at the initial diagnosis of AMKL. Additional cytogenetic and molecular studies confirmed the presence of the CBFA2T3::GLIS2 fusion, but no Ewing sarcoma-specific EWSR1 fusion transcripts were found. Thus, extramedullary CBFA2T3::GLIS2-positive AMKL relapse was confirmed. The patient’s clinical condition gradually worsened, and the patient died 5 months after diagnosis. The presented case demonstrates difficulties in the differential diagnosis between AMKL relapse and the development of a secondary tumor.

… As AML, also known as AMKL, with monosomy 7 has an … We report the successful treatment of childhood AMKL with … used as pretransplant treatment of AMKL with monosomy 7, and we …

Acute myeloid leukemia (AML) associated with Down syndrome (DS-AML) is a unique entity of AML with superior treatment response and overall survival compared with children with non-DS-AML. Despite good outcomes in DS-AML, those who relapse or have refractory disease have poor survival. Successful treatment of these patients is challenged by increased incidence of treatment-related toxicities often encountered with high-dose chemotherapy. Here we report the experience of epigenetic modifying agents (decitabine and vorinostat) followed by fludarabine, cytarabine, and granulocyte colony stimulating growth factor for a child with refractory DS-AML. This combination was well tolerated and resulted in a brief clinical response.

… Here we report a pediatric AMKL patient with novel … AMKL with additional cytogenetic aberrations including chromosome 1p duplication and 3q deletion. After a trial of decitabine and …