Whether mitigation of myeloproliferation improves prognosis of CMML independently of bone marrow response is unknown. Flow-defined classical monocytes (cMo) and immature granulocytes (iGRAN) have not yet been studied as biomarkers of response. We inspected the prognostic value of WBC, circulating monocytes, cMo and iGRANs in the 120 DACOTA (NCT02214407) patients randomized to decitabine (n = 63) or hydroxyurea (n = 57) evaluated after 3 cycles with BM aspiration and complete blood count. Across arms, 59% and 56% patients had monocytes > 1 × 109/L or WBC > 10 × 109/L at the 3- and 6-cycle evaluation respectively. After 6 cycles, persistence of monocytes > 1 × 109/L or WBC > 10 × 109/L increased the hazard of death (HR = 5.38, p = 0.0003) irrespective of treatment, baseline CPSS and persistence of BM blast excess. After 3 cycles, both higher absolute cMo and iGRAN counts independently predicted poorer OS, without significant interaction with treatment arm. Median OS from landmark was 35.1 months in the 28% patients with cMo ≤ 0.94 ×109/L AND iGRAN ≤ 0.40 ×109/L versus 15.3 months in others (p = 0.013). Biomarkers integrating blood counts and flow cytometry may predict CMML prognosis irrespective of treatment.

Chemotherapy resistance in acute myeloid leukemia (AML) remains a major clinical challenge. Integration of multiomic profiling and in vivo functional genomics revealed splicing dysregulation as a determinant of chemoresistance in AML. We uncovered a network involving the splicing regulator SRRM1 and the CLK1/4 and PAK1 kinase families as vulnerabilities in chemoresistant AML cells. Both kinase families are hyperactivated in chemoresistant cells, promoting SRRM1 phosphorylation and altering its scaffolding function. We also identified a relapse-associated PAK1 variant, c.1429G>T p.(Ala477→Ser), that confers chemotherapy resistance. Combined PAK1 and CLK1/4 inhibition recapitulated the splicing changes induced by SRRM1 loss, preferentially targeting chemoresistant AML and enhancing chemotherapy efficacy in cell lines, primary cells, and mouse models. Last, we pinpointed MAP2K5 as a critical downstream effector because missplicing of exons 17 and 18 of MAP2K5 upon SRRM1 depletion sensitized cells to chemotherapy. Our findings highlight a therapeutic strategy to overcome AML relapse by targeting splicing dysregulation.

Abstract FLT3 internal tandem duplications (FLT3-ITD) are major genetic events in acute myeloid leukemia (AML). Although the clinical impact of FLT3-ITD “macroclones” (allelic ratio [AR] ≥0.05) is well established, the significance of low-level FLT3-ITD subclones (“microclones”) remains uncertain. We conducted a post hoc analysis of 1733 patients with newly diagnosed AML enrolled in the Backbone Intergroup 1 trial (ClinicalTrials.gov identifier: NCT02416388). Using next-generation sequencing (NGS), we detected FLT3-ITD microclones (AR between 0.0004 and 0.05) in 17.4% of patients without FLT3-ITD macroclones. Microclones and macroclones (low and high AR) were independently associated with increased relapse risk (cause-specific hazard ratio, 1.50 [95% confidence interval (CI), 1.18-1.91]; 1.98 [1.50-2.62]; and 2.33 [1.69-3.22], respectively) after adjustment for age, white blood cell count, other gene mutations, midostaurin treatment, and allogeneic hematopoietic stem cell transplantation. At 2 years, the cumulative incidence of relapse reached 42.5% (95% CI, 37.0-47.9) in patients with macroclones, 45.1% (38.3-51.6) in patients with microclones, and 29.4% (26.6-32.3) in patients without FLT3-ITD. In NPM1-mutated AML, both microclones and macroclones were associated with higher levels of measurable residual disease (MRD) and increased relapse risk, without independent impact on overall survival after adjustment for MRD. An analysis of paired samples further revealed that 41.8% of relapses in patients with FLT3-ITD microclones at diagnosis were associated with a macroclone at relapse. These findings challenge current risk stratification models and support the integration of NGS-based FLT3-ITD detection into the diagnostic and prognostic workflow for AML. Prospective trials addressing the management of patients with FLT3-ITD microclones are warranted, as is their consideration in future European LeukemiaNet guidelines.

We report a large cohort of 95 adult patients with acute myeloid leukemia (AML) harboring NUP98 rearrangements (NUP98r). Patient characteristics included a young age (median 50 years [IQR 38-64]), 20% of therapy-related AML, a high WBC count (median 52×109/L), normal karyotype in 32%, FLT3-ITD in 48% and WT1 mutations in 34%. NUP98::NSD1 fusion was the most common (54%), and these patients were significantly younger (41 y vs. 61 y), had more de novo AML (94% vs. 64%), higher rates of normal karyotypes (56% vs. 4.5%), FLT3-ITD (76% vs. 18%) and WT1 mutations (50% vs. 16%) than other NUP98r AML. The median overall survival (OS) for the entire cohort was 15.2 months (95% CI, 11.9-20.8) and event-free survival was 5.8 months (2-7.5). Among patients treated intensively (n = 73), age (HR = 2.7), FLT3 inhibitor therapy (HR = 0.45) and hematopoietic stem cell transplant (HR = 0.5) influenced OS in univariate analysis. Compared with NUP98 wild-type (WT) AML, NUP98r patients had a prognosis more similar to that of NUP98 WT ELN adverse patients whether initially classified as intermediate (20.3 months [11.7-30.2]) or adverse (15.7 months [13.5-42.9]). However, treatment with FLT3 inhibitors improved prognosis, with median OS not reached and 5-year OS of 53.3%, approaching that of intermediate-risk patients.

Measurable residual disease (MRD) follow-up is recommended for treatment response evaluation in acute myeloid leukemia (AML) clinical trials according to ELN 2025 guidelines. The aim of this study was to implement a standardized follow-up of patients using a harmonized MRD flow approach across 30 French hematology laboratories participating in AML clinical trials. To obtain comparable results, the network established recommendations from wet-lab procedures to clinical reports. We designed a 3-tube panel with mandatory 8-color common markers per tube, according to ELN recommendations, to identify leukemia-associated immunophenotype/different-from-normal (LAIP/DfN) patterns in bulk cells and leukemic stem cell (LSC)-enriched populations in the CD34+CD38- fraction. A backbone of CD34/CD38/CD45/CD117 was used, completed by lineage markers for the first tube, LSC-associated markers for the second tube, and monocytic and differentiation markers for the third tube. This panel can be used in 8-, 10-, and 12-color formats and implemented on multiple conventional flow cytometer platforms. We propose flow cytometer settings adapted to each platform. Harmonization of sensitivity between the four platforms was performed using 8-peak rainbow beads. Immunostaining was performed after bulk lysis. To detect bias between platforms, the staining index was tested using fresh healthy bone marrow samples in parallel on the four platforms. Regular bone marrow quality-control samples were shared among laboratories for wet external quality assessment (EQA) to verify all steps of the protocol. Finally, standardization of the data analysis strategy obtained in the centers was evaluated using dry EQA by sharing MRD FCS data files. The feasibility of this multicenter approach requires harmonization of instrument sensitivity and sample preparation, as well as training and systematic education of analytical operators.

The hallmark of chronic myelomonocytic leukemia (CMML) is an abnormal increase in circulating monocytes and neutrophils. Several non-exclusive scenarios could explain this accumulation, including extended lifespan in blood and/or increased production in bone marrow (BM). To test these, we generated quantitative, in vivo measurements of how myeloid cells are produced, mature, and survive by using deuterium-glucose incorporation, mathematical modelling, and Bayesian inference, in 25 CMML patients and 10 aged healthy donors. Results showed no evidence for increased lifespans of monocytes and neutrophils in peripheral blood. Conversely, CMML boosts the production of monocytes by ∼7-fold and neutrophils by ∼1.8-fold. The lack of correlation between this increased production and cell subset kinetic parameters supports the hypothesis that an increased number of progenitors is the main source of enhanced myeloid cell production. Beyond this generic observation, kinetic parameters were more divergent in CMML patients than in controls. The most divergent outlier subjects tended to higher IPSS-M scores (Molecular International Prognostic Scoring System for Myelodysplastic Syndromes). Delayed maturation of neutrophils was observed in patients with a SRSF2 mutation, while BM retention of mature monocytes and neutrophils was diversely associated with inflammatory markers. Occasionally, CMML patients release immature granulocytes (iGRANs) into the circulation. We found that these iGRANs had distinct kinetics, including delayed maturation, rapid release, and longer survival in the bloodstream. Overall, these data support a model in which increased myeloid cell production stems from greater progenitor numbers, generating cells with increasingly diverse kinetics as the disease progresses, including a specifically-dysregulated iGRAN population. This trial was registered at www.clinicaltrials.gov as NCT04775121.

Measurable residual disease (MRD) is a major prognostic factor in Core Binding Factor (CBF) AML. KIT or FLT3 mutations also have prognostic relevance, but little is known about their prognostic value when accounting for MRD. We analyzed the prognostic value of genetic alterations adjusting for early MRD response in adult CBF-AML patients. We grouped data from the retrospective multicenter study RetroCBF (NCT05070208, training set) and the prospective CBF-2006 trial (NCT00428558, validation set). Centralized high-throughput sequencing was performed with 36 genes. 656 CBF-AML patients in first CR were included between 2007 and 2020 (RetroCBF n = 461; CBF-2006 n = 195). In a LASSO-penalized model including MRD and genetic alterations performed in the RetroCBF training cohort, KIT-TKD in RUNX1::RUNX1T1 and FLT3-ITD in CBFB::MYH11 were associated with a higher risk of relapse. Including these genetic alterations with MRD in the training cohort, 3-year cumulative incidence of relapse was 22% (95%CI:13-33%) in low-risk patients (MRD low AND no KIT-TKD [RUNX1::RUNX1T1] or FLT3-ITD [CBFB::MYH11]) versus 53% (95%CI 46%-60%) in high-risk patients (csHR=3.21 [95%CI:1.83-5.62], p < 0.0001). These results were confirmed in the CBF-2006 validation cohort. KIT-TKD mutations in RUNX1::RUNX1T1 and FLT3-ITD in CBFB::MYH11 worsen prognosis independently of MRD and must be included in risk stratification of CBF AMLs.

PURPOSE:Chronic myelomonocytic leukemia (CMML) is a rare myeloid neoplasm characterized by clinical heterogeneity and is associated with poor outcomes. To date, limited molecular information has been incorporated into disease classification and risk stratification. We aimed to integrate genomic features into the clinical decision-making process for CMML. PATIENTS AND METHODS:We analyzed a retrospective cohort of 3013 patients with CMML (training set) and a prospective population of 516 patients (validation set). Using an innovative framework for multimodal data analysis, we developed molecular-based disease taxonomy and prognostication. RESULTS:Unsupervised clustering identified nine entities with distinct genomic features and outcomes (P < .001), including splicing machinery, transcription factors, signal transduction and tyrosine kinase pathways aberrations, and high-risk molecular signatures. Notably, 15% of patients showed molecular/clinical overlap with other myeloid neoplasms. We integrated molecular and clinical information to build the international CMML Prognostic Scoring System (iCPSS), incorporating mutations in nine genes together with hematologic parameters and cytogenetic abnormalities. The iCPSS identified five groups with distinct probability of overall and leukemia-free survival in both training and validation cohorts (P < .001), outperforming existing prognostic models. Importantly, 55% of patients were reassigned to higher or lower risk groups by the iCPSS. Decision analysis demonstrated that iCPSS could refine the optimal timing of allogeneic transplantation at the individual level; compared with conventional prognostic tools, iCPSS-based decision modeling changed transplantation strategy in 31% of cases, resulting in a significant gain-in-life expectancy for eligible patient population (P < .001). A federated learning platform was implemented to enable continuous, privacy-preserving model update across multiple centers. CONCLUSION:Molecular information improves CMML classification and prognostication, supports more effective clinical decision making, and potentially refines the design of clinical trials.

Abstract Introduction Patients (pts) with core-binding factor (CBF) AML (defined by inv(16)(p13.1q22) or t(16;16)(p13.1;q22)/CBFB::MYH11 or t(8;21)(q22;q22.1)/RUNX1::RUNX1T1 gene fusions) are considered to have favorable risk disease when treated with intensive chemotherapy regimens. However, since these pts were excluded from pivotal trials evaluating venetoclax in combination with hypomethylating agents (HMA/Ven) or low-dose cytarabine (LDAC/Ven), little is known about the efficacy of these regimens in CBF AML pts ineligible for intensive treatment. Case series suggest that pts with CBFB::MYH11 respond well to HMA/Ven, whereas those with RUNX1::RUNX1T1 may be less responsive (Zhang et al., 2023, Shen et al., 2025). Given the lack of approved and effective therapies for older or frail pts with CBF AML besides HMA/Ven, this study aimed to assess its efficacy in this specific patient population. Methods Based on data from seven European study group registries (PETHEMA, DATAML, CELL, ALFA, NCRI, PALG, and SAL), we retrospectively analyzed adult pts with newly diagnosed CBF AML treated with HMA/Ven. CBF fusions were identified using conventional karyotyping, FISH, PCR and/or NGS. For response evaluation, ELN 2022 criteria were used, and best response within six HMA/Ven cycles is reported. The median overall survival (mOS) was estimated using the Kaplan-Meier method. Statistical analyses were performed using GraphPad Prism v.10.5.0. Results We identified 53 pts with newly diagnosed CBF AML (27 (51%) with CBFB::MYH11 and 26 (49%) with RUNX1::RUNX1T1) treated with HMA/Ven between September 2019 and July 2025. The median age of the entire cohort was 76 years (range, 30-86), and 21 pts (40%) were female. ECOG performance status was ≥2 in 17 pts (35%). Eight pts (20%) had AML post-cytotoxic therapy. According to the European LeukemiaNet (ELN) 2024 risk classification, 70%, 28%, and 2% of pts had favorable, intermediate, and adverse risk disease, respectively. The most common secondary genetic alterations were mutations in NRAS (31%), TET2 (30%), KIT (29%), KRAS (23%) and DNMT3A (14%). Except for a higher KRAS mutation prevalence in pts with CBFB::MYH11 (44% vs. 5%; p=0.051), there were no significant differences in baseline characteristics between CBFB::MYH11 or RUNX1::RUNX1T1 subgroups. None of the pts had previously been exposed to HMA or Ven, and most pts (95%) received Ven in combination with azacitidine. The median planned Ven schedule (cycle one) was 21 days (range, 7-28), and the median number of administered HMA/Ven cycles was 4 (range, 1-24). Two pts underwent subsequent allogeneic hemopoietic cell transplantation. The composite complete remission rate (CRc, CR + CRi) of the entire cohort was 69%, and was similar for pts with CBFB::MYH11 orRUNX1::RUNX1T1 fusions(67% vs. 72%,p=0.564). Pts with ELN 2024 intermediate risk mutations (i.e., FLT3-ITD, NRAS and/or KRAS) had a CRc rate similar to those without any of these variants (68% vs. 73%,p=0.752). Also, the CRc rate of pts with KIT mutations was comparable to wild-type pts (68% vs 79%,p=0.29). The 60-day mortality rate was 8%. After a median follow-up of 14 months, the mOS of the entire cohort was 13 months, with corresponding 12-month and 24-month OS rates of 54% and 39%, respectively. The mOS of pts with RUNX1::RUNX1T1 was similar to those with CBFB::MYH11 (12 months vs. 14 months, p=0.447). As compared to the corresponding wild-type pts, neither ELN 2024 intermediate risk variants nor KIT mutations adversely impacted mOS (FLT3-ITD/NRAS/KRAS, 11 months vs. NR, p=0.191; KIT, 14 months vs. 12 months, p=0.681). Conclusions Based on our analysis in a larger cohort of international pts, treatment with HMA/Ven seems to be a valuable treatment option for CBF AML pts ineligible for intensive chemotherapy. In contrast to previous studies in mostly Chinese cohorts, we did not observe a significant difference in response or survival between pts with AML with CBFB::MYH11 and those with RUNX1::RUNX1T1. With a mOS of around 12 months, outcomes of HMA/Ven treated CBF AML pts appear less favorable than those previously reported for pts with ELN 2024 favorable risk disease, and similar to those observed in ELN 2024 intermediate risk non-CBF AML pts, irrespective of FLT3-ITD, NRAS and/or KRAS mutations. Therefore, we propose that all pts with CBF AML treated with HMA/Ven should be provisionally classified as having ELN 2024 intermediate risk disease.

Introduction Therapy-related CBF-AMLs represent approximately 10% of all CBF-AMLs and are associated with poorer outcomes, partly due to the associated solid tumor. Existing studies are small, and more data—especially NGS and cytogenetics—are needed to better define their characteristics and prognosis. Methods We analyzed data from a retrospective multicenter study (NCT05070208) and the prospective CBF-2006 trial (NCT00428558, Jourdan et al. 2014) from the French AML intergroup, including CBF-AML patients diagnosed between 2007–2020. Cases with prior chemo- or radiotherapy were classified as therapy-related (t-AML). Baseline characteristics were compared in the overall cohort. Outcomes were assessed in a sub-population of fit patients (≤80 years, cancer in remission, intensive chemotherapy). Centralized NGS was performed using 40- and 68-gene panels (36 genes in common), and MRD was assessed by RT-qPCR for RUNX1::RUNX1T1 and CBFB::MYH11. Results Among 749 CBF-AML patients included between 2007 and 2021, 78 had t-AML. t-AML patients were older (median age: 59 vs. 45 years, p<0.001), more likely to be female (68% vs. 44%, p<0.001), and had lower white blood cell counts (WBC) at diagnosis (median: 6 vs. 15 G/L, p<0.001). was the most common prior neoplasm (42%). Median interval from chemo/radiotherapy to t-AML onset was 38 months (IQR [interquartile range]: 25–69). Neoplasms were in complete remission after chemotherapy (74%) and/or radiotherapy (49%) at CBF-AML diagnosis in 83% pts and remained in sustained remission in 78% after a median follow up of 1.8 years. The distribution of RUNX1::RUNX1T1 and CBFB::MYH11 subtypes was similar between therapy-related and de novo cases (44% and 43% for RUNX1::RUNX1T1, p>0.9). Cytogenetically, X chromosome deletions were more frequent in t-AML (16% vs. 8%, p=0.016). t-AMLs showed fewer on NGS (63% vs. 75%, p = 0.019), and fewer FLT3 mutations (10% vs. 24%, p = 0.03). No other difference was observed in the mutational landscape of t-AML, including KIT and TP53 alterations. In the selected population of patients without active cancer at AML diagnosis and treated with intensive chemotherapy (n=693, including 57 t-AML), induction regimens were mainly based on 7+3 ( in t-AML vs 72% in non-t-AML, p=0.07) and consolidation courses on intermediate/high dose cytarabine courses (93% in t-AML vs 90% in non-t-AML, p=0.64). Gemtuzumab-ozogamycin was added to Cx in 9% of t-AML (vs. 10% of non-t-AML, p=1.0). Allogeneic transplant in first complete remission was performed in 9% of t-AML and 5% of non-t-AML (p=0.21). Therapy-related AML patients had a CR/CRp rate of 95%, not different from de novo patients (95%, p=0.74). MRD after one cycle of induction was not different in t-AML in bone marrow (median: 0.20% [IQR: 0.04-0.82%] vs. 0.17% [IQR: 0.03-0.49%], p=0.50) nor in peripheral blood (median: 0.02% [IQR: 0.002-0.14%] vs. 0.03% [IQR: 0.001-0.19%], p=0.85). With a median follow-up of 5.3 years (IQR :3.9-6.8), the 3-year cumulative incidence (CI) of relapse was 41% (95%CI [confidence interval]:27%-54%) in t-AML patients and 38% (95%CI:34%-42%) in non-t-AML patients (csHR=1.07 [95%CI:0.69-1.68], p=0.76). No difference was also observed for non-relapse mortality (NRM) (3-year CI-NRM: 2% [95%CI:0%-9%] for t-AML vs. 3% [95%CI:2%-5%] for non-t-AML, csHR=0.87 [95%CI:0.21-3.66], p=0.85). Overall survival (OS) was lower in t-AML in univariable analysis (3-year OS: 62% [95%CI:50%-77%] in t-AML vs 79% [95%CI:75%-82%] in non-t-AML, p=0.03). Nevertheless, this was not confirmed in multivariable analysis (HR=1.36, 95%CI:0.84-2.18, p=0.21 for t-AML) when accounting for age (per 10 years of age HR=1.27, 95%CI:1.14-1.42, p<0.001), WBC count (log10 scale HR=1.25, 95%CI:0.94-1.65, p=0.12), and CBF subtype (HR=1.19, 95%CI:0.87-1.62, p=0.29 for RUNX1::RUNX1T1). In patients who experienced relapse (n=249 including 21 t-AML), OS after relapse was dismal in t-AML (16% [95%CI:6%-45%] vs 56% [95%CI:50%-64%], p<0.0001). Conclusion This study shows that therapy-related CBF-AML patients are older, have lower WBC at diagnosis, and present with similar molecular profiles compared to de novo cases. Among a homogenous cohort of patients without active cancer and treated with intensive chemotherapy, there were no differences in CR/CRp rates, relapse incidence, or non-relapse mortality. Unlike previous studies, overall survival was not significantly different after multivariable adjustment for age, WBC count, and CBF subtype.

ABSTRACT:The prognostic impact of monocytic differentiation in patients with acute myeloid leukemia (AML) receiving venetoclax (Ven) and azacitidine (Aza) remains unclear. In a prospective cohort of 86 newly diagnosed patients with AML treated with Ven-Aza, we used multiparametric flow cytometry (MFC) to define monoblasts as AML blasts coexpressing ≥2 monocytic markers (CD4, CD36, and CD64) per European LeukemiaNet (ELN) guidelines. Patients with higher monoblasts/CD45+ proportions had lower complete response rates (odds ratio, 0.24; P = .005) and significantly shorter overall survival (OS; 4.0 vs 14.9 months; P = .003). A ≥10% monoblasts/CD45+ threshold, identified via maximally selected rank statistics, stratified patients into monoblasthigh (≥10%) and monoblastlow (<10%) groups. MFC reclassified 20% of French-American-British (FAB) non-M4/5 and 15% of FAB M4/5 cases into monoblasthigh and monoblastlow groups, respectively. Multivariable analysis confirmed monoblasthigh status as an independent adverse prognostic factor for OS (hazard ratio [HR], 1.95; P = .023), with a particularly strong impact in ELN 2024 favorable-risk patients (HR, 2.81; P = .024). Our findings highlight monocytic differentiation, assessed via MFC, as a key predictor of Ven-Aza resistance and poor survival, independent of genetic classification. Given its availability in routine diagnostics, MFC-based monocytic assessment could improve AML risk stratification and treatment decisions in patients eligible for less intensive therapies. This trial was registered at www.clinicaltrials.gov as #NCT05326919.

Supplementary Table 1. Karyotypes of LH-ALL patients at diagnosis. Supplementary Table 2. Somatic variants detected in LH-ALL patients at diagnosis. Supplementary Table 3. ARCH related variants detected in LH-ALL patients at remission. Supplementary Table 4. Minimal residual disease values of remission samples used for mutation analysis. Supplementary Table 5. Somatic alterations in cell populations from diagnostic samples (BMMC) based on single-cell analyses. Supplementary Table 6. Somatic alterations in FACS-sorted cell populations from diagnostic samples. Supplementary Table 7. Panel of genes for targeted sequencing. Supplementary Table 8. Single cell DNA amplicons for genotyping and LOH analyses. Supplementary Table 9. Single cell DNA amplicons for B-ALL clono-specific IG/TR detection. Supplementary Table 10. ADT-seq panel and spike-in antibodies. Supplementary Table 11. Single cell sequencing metrics.

PURPOSE:PPM1D, a central regulator of the DNA damage response, is commonly mutated in therapy-related clonal hematopoiesis, acute myeloid leukemia (AML), and myelodysplastic syndromes (MDS). PPM1D mutations have been shown to expand under the selective pressure of DNA-damaging chemotherapy. However, whether PPM1D mutations promote the development of hematologic malignancies remains unclear. EXPERIMENTAL DESIGN:We characterized the clinical and genomic profiles of 112 PPM1D-mutated patients across the spectrum of myeloid disorders using a combination of bulk and single-cell analyses on diagnostic and longitudinal samples. RESULTS:Among all patients, 78% had a history of primary cancer, with DNMT3A and TP53 being the most frequently comutated genes. In 10 patients with high-grade serous ovarian cancer, longitudinal analysis showed variable dynamics of PPM1D-mutant clones, with 81% of clones expanding during exposure to alkylating agents. Clonal hierarchy estimation revealed that 44% of patients with PPM1D-mutated AML had a PPM1D mutation in the founder clone, with rare TP53 comutations. Both patients with TP53 wild-type and TP53-mutated AML had poor overall survival. Single-cell DNA and surface protein analysis in seven patients confirmed that PPM1D mutations can arise in the founding clone and are associated with the expression of leukemic markers. CONCLUSIONS:PPM1D mutations found in clonal hematopoiesis can spontaneously regress after treatment discontinuation; however, they can also be found in the dominant clone in AML/MDS.