Unlocking the potential: A novel prognostic index signature for acute myeloid leukemia.

Acute myeloid leukemia (AML) is an aggressive malignancy characterized by challenges in treatment, including drug resistance and frequent relapse. Recent research highlights the crucial roles of tumor microenvironment (TME) in assisting tumor cell immune escape and promoting tumor aggressiveness. This study delves into the interplay between AML and TME. Through the exploration of potential driver genes, we constructed an AML prognostic index (AMLPI). Cross-platform data and multi-dimensional internal and external validations confirmed that the AMLPI outperforms existing models in terms of areas under the receiver operating characteristic curves, concordance index values, and net benefits. High AMLPIs in AML patients were indicative of unfavorable prognostic outcomes. Immune analyses revealed that the high-AMLPI samples exhibit higher expression of HLA-family genes and immune checkpoint genes (including PD1 and CTLA4), along with lower T cell infiltration and higher macrophage infiltration. Genetic variation analyses revealed that the high-AMLPI samples associate with adverse variation events, including TP53 mutations, secondary NPM1 co-mutations, and copy number deletions. Biological interpretation indicated that ALDH2 and SPATS2L contribute significantly to AML patient survival, and their abnormal expression correlates with DNA methylation at cg12142865 and cg11912272. Drug response analyses revealed that different AMLPI samples tend to have different clinical selections, with low-AMLPI samples being more likely to benefit from immunotherapy. Finally, to facilitate broader access to our findings, a user-friendly and publicly accessible webserver was established and available at http://bioinfor.imu.edu.cn/amlpi. This server provides tools including TME-related AML driver genes mining, AMLPI construction, multi-dimensional validations, AML patients risk assessment, and figures drawing.

Data-driven modeling of core gene regulatory network underlying leukemogenesis in IDH mutant AML.

Acute myeloid leukemia (AML) is characterized by uncontrolled proliferation of poorly differentiated myeloid cells, with a heterogenous mutational landscape. Mutations in IDH1 and IDH2 are found in 20% of the AML cases. Although much effort has been made to identify genes associated with leukemogenesis, the regulatory mechanism of AML state transition is still not fully understood. To alleviate this issue, here we develop a new computational approach that integrates genomic data from diverse sources, including gene expression and ATAC-seq datasets, curated gene regulatory interaction databases, and mathematical modeling to establish models of context-specific core gene regulatory networks (GRNs) for a mechanistic understanding of tumorigenesis of AML with IDH mutations. The approach adopts a new optimization procedure to identify the top network according to its accuracy in capturing gene expression states and its flexibility to allow sufficient control of state transitions. From GRN modeling, we identify key regulators associated with the function of IDH mutations, such as DNA methyltransferase DNMT1, and network destabilizers, such as E2F1. The constructed core regulatory network and outcomes of in-silico network perturbations are supported by survival data from AML patients. We expect that the combined bioinformatics and systems-biology modeling approach will be generally applicable to elucidate the gene regulation of disease progression.

Comparison of clinical outcomes of several risk stratification tools in newly diagnosed AML patients: A real-world evidence in our current therapeutic era.

BACKGROUND OF THE STUDY: AML classification tools have been developed to stratify the risk at AML diagnosis. There is a need to evaluate these tools in the current therapeutic era. COHORT CHARACTERISTICS: In this retrospective study, we compared five classifiers: ELN 2017, ELN 2022, ALFA classifier, Papaemmanuil et al. classifier, and Lindsley et al. classifier, in a real-life cohort of 281 patients newly diagnosed for AML in Nice University Hospital. In our cohort median age was 68 years old, sex ratio was M/F 56%/44%, performance status was lower than 2 in 73.1% of patients, AML subtype was "De novo" in 71.5%, "secondary" in 22.4%, and "therapy-related" in 6.0% of patients. Intensive chemotherapy was used in 53.0% of patients, and non-intensive chemotherapy in 40.6% of patients. Molecular analysis was available in a large majority of patients and the main mutations found were NPM1 (22.7%), DNMT3A (17.4%), TP53 (13.1%), TET2 (12.4%), and FLT3-ITD (12.4%). RESULTS: In our findings, the comparison of overall survival between the three prognostic groups in the global cohort was statistically significant in all classifiers: ELN 2017 p < 0.0001, ELN 2022 p < 0.0001, ALFA classifier p < 0.0001, Papaemmanuil classifier p < 0.0001, Lindsley classifier p = 0.001. ELN 2017, ELN 2022, ALFA classifier, Papaemmanuil classifier, and Lindsley classifier were calculated respectively in 99%, 99%, 89%, 90%, and 89% of patients. CONCLUSIONS: Using Akaike's information criteria (AIC) to compare all five classifiers, ELN 2022 is the best classifier into younger and older patients and for prognosis.

Regulation of HOX gene expression in AML.

As key developmental regulators, HOX cluster genes have varied and context-specific roles in normal and malignant hematopoiesis. A complex interaction of transcription factors, epigenetic regulators, long non-coding RNAs and chromatin structural changes orchestrate HOX expression in leukemia cells. In this review we summarize molecular mechanisms underlying HOX regulation in clinical subsets of AML, with a focus on NPM1 mutated (NPM1mut) AML comprising a third of all AML patients. While the leukemia initiating function of the NPM1 mutation is clearly dependent on HOX activity, the favorable treatment responses in these patients with upregulation of HOX cluster genes is a poorly understood paradoxical observation. Recent data confirm FOXM1 as a suppressor of HOX activity and a well-known binding partner of NPM suggesting that FOXM1 inactivation may mediate the effect of cytoplasmic NPM on HOX upregulation. Conversely the residual nuclear fraction of mutant NPM has also been recently shown to have chromatin modifying effects permissive to HOX expression. Recent identification of the menin-MLL interaction as a critical vulnerability of HOX-dependent AML has fueled the development of menin inhibitors that are clinically active in NPM1 and MLL rearranged AML despite inconsistent suppression of the HOX locus. Insights into context-specific regulation of HOX in AML may provide a solid foundation for targeting this common vulnerability across several major AML subtypes.

Elucidation of pericholangitis and periductal fibrosis in cholestatic liver diseases via extracellular vesicles released by polarized biliary epithelial cells.

Cholestatic liver diseases causes inflammation and fibrosis around bile ducts. However, the pathological mechanism has not been elucidated. Extracellular vesicles (EVs) are released from both the basolateral and apical sides of polarized biliary epithelial cells. We aimed to investigate the possibility that EVs released from the basolateral sides of biliary epithelial cells by bile acid stimulation induce inflammatory cells and fibrosis around bile ducts, and they may be involved in the pathogenesis of cholestatic liver disease. Human biliary epithelial cells (H69) were grown on cell culture inserts and stimulated with chenodeoxycholic acid + IFN-γ. Human THP-1-derived M1-macrophages, LX-2 cells, and KMST-6 cells were treated with the extracted basolateral EVs, and inflammatory cytokines and fibrosis markers were detected by RT-PCR. Highly expressed proteins from stimulated EVs were identified, and M1-macrophages, LX-2, KMST-6 were treated with these recombinant proteins. Stimulated EVs increased the expression of TNF, IL-1ß, and IL-6 in M1-macrophages, TGF-ß in LX-2 and KMST-6 compared with the corresponding expression levels in unstimulated EVs. Nucleophosmin, nucleolin, and midkine levels were increased in EVs from stimulated cells compared with protein expression in EVs from unstimulated cells. Leukocyte cell-derived chemotaxin-2 (LECT2) is highly expressed only in EVs from stimulated cells. Stimulation of M1-macrophages with recombinant nucleophosmin, nucleolin, and midkine significantly increased the expression of inflammatory cytokines. Stimulation of LX-2 and KMST-6 with recombinant LECT2 significantly increased the expression of fibrotic markers. These results suggest that basolateral EVs are related to the development of pericholangitis and periductal fibrosis in cholestatic liver diseases.NEW & NOTEWORTHY Our research elucidated that the composition of basolateral EVs from the biliary epithelial cells changed under bile acid exposure and the basolateral EVs contained the novel inflammation-inducing proteins NPM, NCL, and MK and the fibrosis-inducing protein LECT2. We report that these new results are possible to lead to the potential therapeutic target of cholestatic liver diseases in the future.

Porcine circovirus type 2 infection promotes the SUMOylation of nucleophosmin-1 to facilitate the viral circular single-stranded DNA replication.

The mechanism of genome DNA replication in circular single-stranded DNA viruses is currently a mystery, except for the fact that it undergoes rolling-circle replication. Herein, we identified SUMOylated porcine nucleophosmin-1 (pNPM1), which is previously reported to be an interacting protein of the viral capsid protein, as a key regulator that promotes the genome DNA replication of porcine single-stranded DNA circovirus. Upon porcine circovirus type 2 (PCV2) infection, SUMO2/3 were recruited and conjugated with the K263 site of pNPM1's C-terminal domain to SUMOylate pNPM1, subsequently, the SUMOylated pNPM1 were translocated in nucleoli to promote the replication of PCV2 genome DNA. The mutation of the K263 site reduced the SUMOylation levels of pNPM1 and the nucleolar localization of pNPM1, resulting in a decrease in the level of PCV2 DNA replication. Meanwhile, the mutation of the K263 site prevented the interaction of pNPM1 with PCV2 DNA, but not the interaction of pNPM1 with PCV2 Cap. Mechanistically, PCV2 infection increased the expression levels of Ubc9, the only E2 enzyme involved in SUMOylation, through the Cap-mediated activation of ERK signaling. The upregulation of Ubc9 promoted the interaction between pNPM1 and TRIM24, a potential E3 ligase for SUMOylation, thereby facilitating the SUMOylation of pNPM1. The inhibition of ERK activation could significantly reduce the SUMOylation levels and the nucleolar localization of pNPM1, as well as the PCV2 DNA replication levels. These results provide new insights into the mechanism of circular single-stranded DNA virus replication and highlight NPM1 as a potential target for inhibiting PCV2 replication.

Clinical and genetic characteristics predict outcomes of acute myeloid leukemia patients with FLT3 mutations receiving venetoclax-based therapy.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease, and its heterogeneity is associated with treatment response. Despite the demonstrated success of venetoclax (VEN)-based therapy for AML, the effect of FLT3 mutations on the efficacy of the therapy is poorly understood. We aimed to compare the efficacy of VEN-based therapy between FLT3-mutated (FLT3mut ) and FLT3 wild-type (FLT3wt ) patients and identify the predictors of efficacy in FLT3mut patients. METHODS: A total of 266 AML patients (127 newly diagnosed [ND] and 139 refractory/relapsed [R/R]) receiving VEN-based regimens were enrolled in this study. A retrospective analysis was performed, and the treatment responses and overall survival (OS) of FLT3mut and FLT3wt patients were compared. Logistic regression and Cox proportional hazards model were applied to examine the clinical and genetic predictors of outcomes. RESULTS: With a median of two cycles of VEN-based therapy, for the ND AML cohort, the FLT3mut group had a comparable composite complete remission (CRc) rate with the FLT3wt group (79.3% vs. 61.2%, p = 0.072). For the R/R AML cohort, the FLT3mut group exhibited a lower CRc rate than the FLT3wt group. With a median follow-up of 8.6 months (95% confidence interval [CI], 8.0-10), the median OS observed in the FLT3mut and FLT3wt groups for both cohorts were close (14.0 vs. 19.9 months, p = 0.356; 10.0 vs. 11.9 months, p = 0.680). For the ND AML cohort, in FLT3mut patients, MRD-positive and RNA-splicing mutation predicted inferior survival (hazard ratio [HR], 10.3; 95% CI: 2.0-53.8; p = 0.006; HR 11.3; 95% CI: 1.2-109.3; p = 0.036, respectively). For the R/R AML cohort, in FLT3mut patients, adverse ELN risk was associated with an inferior response (odds ratio [OR], 0.2; 95% CI: 0.1-0.8; p = 0.025), whereas NPM1 co-mutation was associated with a superior response (57.1%; OR, 6.7; 95% CI: 1.5-30.1; p = 0.014). CR/CRi predicted a better survival (HR 0.2; 95% CI: 0.1-0.8; p = 0.029), while DNMT3A mutation predicted an inferior survival (HR, 4.6; 95% CI: 1.4-14.9; p = 0.011). CONCLUSIONS: FLT3 mutations may influence response to VEN-based therapy in R/R AML patients but not in ND AML patients. Furthermore, clinical and genetic characteristics could predict outcomes of FLT3mut patients receiving VEN-based therapy.

Clinical characteristics and prognosis of acute myeloid leukemia patients with Runt-related transcription factor 1 mutation: A single-center retrospective analysis.

This study aimed to investigate the clinical characteristics and prognosis of Runt-related transcription factor 1 (RUNX1) mutant acute myeloid leukemia (AML) patients by comparing the features of AML patients with or without RUNX1 mutation. We retrospectively analyzed 180 AML patients including 36 AML patients with mutant RUNX1(AML-RUNX1mut ) and 144 AML patients with wild-type RUNX1(AML-RUNX1wt ) were selected using the case-pair method(1:4). Compared to AML-RUNX1wt , AML-RUNX1mut showed higher frequency of ASXL1 (p < 0.001), SRSF2 (p < 0.001), BCORL1 (p < 0.001), RAS (p = 0.010) mutations, and absent NPM1 mutations (p = 0.022). The 3-year overall survival (OS) and disease-free survival (DFS) of AML-RUNX1mut and AML-RUNX1wt were 73.1% versus 68.0% (p = 0.64) and 80.7% versus 71.6% (p = 0.37), respectively. AML-RUNX1mut receiving allogeneic hematopoietic cell transplantation (allo-HSCT) showed better survival than those who did not receive allo-HSCT (3-year OS, 84.3% vs. 52.7%; p = 0.006). Multivariate analysis showed that EZH2 mutation (p = 0.003), white blood cell (WBC) ≥30 × 109 /L (p = 0.036) and age ≥60 years (p = 0.038) were significant independent risk factors for inferior OS of AML-RUNX1mut ; WBC ≥30 × 109 /L (p = 0.013) and DNMT3A mutation (p = 0.045) were significant independent risk factors for shorter DFS of AML-RUNX1mut . In conclusion, AML-RUNX1mut showed unique clinical characteristics, but the survival between AML-RUNX1mut and AML-RUNX1wt were comparable. EZH2 co-mutation, DNMT3A co-mutation, old age and high WBC count were associated with inferior survival of AML-RUNX1mut . Allo-HSCT can significantly improve the prognosis of AML-RUNX1mut .

[Clinical Significance of Genetic and Molecular Changes in Primary Myeloid Sarcoma].

OBJECTIVE: To investigate the clinical significance of genetic and molecular changes in primary myeloid sarcoma (MS). METHODS: Fourteen patients with primary MS were selected in Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences, The First People's Hospital of Lianyungang from September 2010 to December 2021. AML1-ETO fusion, PML-RARα fusion and CBFß breakage were detected by fluorescence in situ hybridization (FISH), and the mutations of NPM1, CEBPA, FLT3, RUNX1, ASXL1, KIT and TP53 genes were detected by new generation sequencing (NGS). RESULTS: Among 14 patients, the MS occurred in bone, breast, epididymis, lung, chest wall, cervix, small intestine, ovary, lymph nodes and central nervous system. The tumor cells expressed MPO (13 cases), CD34 (7 cases), CD43 (8 cases), CD68 (7 cases), CD99 (8 cases) and CD117 (6 cases). Cytogenetic abnormalities were observed in 4 cases, including 3 cases of AML1-ETO fusion and 1 case of CBFß breakage, while no PML-RARα fusion was detected. There were no significant differences in overall survival (OS) and leukemia-free survival (LFS) between patients with and without AML1-ETO fusion/CBFß breakage (both P >0.05). Among the 14 patients, the number of NPM1, CEBPA, FLT3-ITD, RUNX1, ASXL1, KIT and TP53 gene mutations was 5, 3, 5, 3, 2, 2, 1, respectively, of which 7 cases had at least one mutation in FLT3-ITD, RUNX1, ASXL1 and TP53 gene. The OS and LFS of patients with FLT3-ITD, RUNX1, ASXL1 or TP53 mutation were shorter than those without mutations (both P <0.01). CONCLUSION: The genetic and molecular abnormalities of primary MS can be detected by FISH and NGS techniques. FLT3-ITD, RUNX1, ASXL1 or TP53 mutation indicates a worse prognosis, but further clinical studies are needed to confirm it.

ZNF692 regulates nucleolar morphology by interacting with NPM1 and modifying its self-assembly properties.

The nucleolus, a membrane-less organelle, is responsible for ribosomal RNA transcription, ribosomal RNA processing, and ribosome assembly. Nucleolar size and number are indicative of a cell's protein synthesis rate and proliferative capacity, and abnormalities in the nucleolus have been linked to neurodegenerative diseases and cancer. In this study, we demonstrated that the nucleolar protein ZNF692 directly interacts with nucleophosmin 1 (NPM1). Knocking down ZNF692 resulted in the nucleolar redistribution of NPM1 in ring-like structures and reduced protein synthesis. Purified NPM1 forms spherical condensates in vitro but mixing it with ZNF692 produces irregular condensates more closely resembling living cell nucleoli. Our findings indicate that ZNF692, by interacting with NPM1, plays a critical role in regulating nucleolar architecture and function in living cells.

Mapping AML heterogeneity - multi-cohort transcriptomic analysis identifies novel clusters and divergent ex-vivo drug responses.

Subtyping of acute myeloid leukaemia (AML) is predominantly based on recurrent genetic abnormalities, but recent literature indicates that transcriptomic phenotyping holds immense potential to further refine AML classification. Here we integrated five AML transcriptomic datasets with corresponding genetic information to provide an overview (n = 1224) of the transcriptomic AML landscape. Consensus clustering identified 17 robust patient clusters which improved identification of CEBPA-mutated patients with favourable outcomes, and uncovered transcriptomic subtypes for KMT2A rearrangements (2), NPM1 mutations (5), and AML with myelodysplasia-related changes (AML-MRC) (5). Transcriptomic subtypes of KMT2A, NPM1 and AML-MRC showed distinct mutational profiles, cell type differentiation arrests and immune properties, suggesting differences in underlying disease biology. Moreover, our transcriptomic clusters show differences in ex-vivo drug responses, even when corrected for differentiation arrest and superiorly capture differences in drug response compared to genetic classification. In conclusion, our findings underscore the importance of transcriptomics in AML subtyping and offer a basis for future research and personalised treatment strategies. Our transcriptomic compendium is publicly available and we supply an R package to project clusters to new transcriptomic studies.

Complex karyotype but not other cytogenetic abnormalities is associated with worse posttransplant survival of patients with nucleophosmin 1-mutated acute myeloid leukemia: A study from the European Society for Blood and Marrow Transplantation Acute Leukemia Working Party.

In the 2022 European LeukemiaNet classification, patients with nucleophosmin 1 (NPM1)-mutated acute myeloid leukemia (AML) were classified in the adverse-risk category in the presence of high-risk cytogenetics (CG). Nonetheless, the impact of various CG aberrations on posttransplant outcomes remains to be unraveled. This registry study analyzed adult patients with NPM1-mutated de novo AML who underwent their first allogeneic hematopoietic cell transplantation in the first complete remission from 2005 to 2021. A total of 3275 patients were identified, 2782 had normal karyotype, 493 had chromosomal aberrations including 160 with adverse-risk CG, 72 patients had complex karyotype (CK), and 66 monosomal karyotype (MK). Overall, 2377 (73%) patients had FLT3-ITD. On univariate analysis, only FLT3-ITD, minimal/measurable residual disease (MRD) positivity and CK, but not abnormal CG, affected posttransplant outcomes. On multivariable analysis, CK was associated with lower overall survival (OS) (hazard ratio [HR] 1.72, p = .009). In the subgroup of 493 patients with aberrant CG, the 2-year leukemia-free survival (LFS) and OS were around 61% and 68%, respectively. On multivariable analysis for this subgroup, CK and MRD positivity were associated with increased risk of relapse (HR 1.7, p = .025; and 1.99, p = .003 respectively) and worse LFS (HR 1.62, p = .018; and 1.64, p = .011 respectively) while FLT3-ITD, MK, or other CG abnormalities had no significant effect. Importantly, CK negatively affected OS (HR 1.91, p = .002). In the first complete remission transplant setting, CK was found as the only cytogenetic risk factor for worse outcomes in NPM1-mutated AML. Nevertheless, even for this subgroup, a significant proportion of patients can achieve long-term posttransplant survival.

Droplet digital PCR for sensitive relapse detection in acute myeloid leukaemia patients transplanted by reduced intensity conditioning.

INTRODUCTION: Follow-up after allogeneic transplantation in acute myeloid leukaemia (AML) is guided by measurable residual disease (MRD) testing. Quantitative polymerase chain reaction (qPCR) is the preferred MRD platform but unfortunately, 40%-60% of AML patients have no high-quality qPCR target. This study aimed to improve MRD testing by utilising droplet digital PCR (ddPCR). ddPCR offers patient-specific monitoring but concerns of tracking clonal haematopoiesis rather than malignant cells prompt further validation. METHODS: Retrospectively, we performed MRD testing on blood and bone marrow samples from AML patients transplanted by reduced-intensity conditioning. RESULTS: The applicability of ddPCR was 39/42 (92.9%). Forty-five ddPCR assays were validated with a 0.0089% median sensitivity. qPCR targeting NPM1 mutation detected relapse 46 days before ddPCR (p = .03). ddPCR detected relapse 34.5 days before qPCR targeting WT1 overexpression (p = .03). In non-relapsing patients, zero false positive ddPCR MRD relapses were observed even when monitoring targets associated with clonal haematopoiesis such as DNMT3A, TET2, and ASXL1 mutations. CONCLUSION: These results confirm that qPCR targeting NPM1 mutations or fusion transcripts are superior in MRD testing. In the absence of such targets, ddPCR is a promising alternative demonstrating (a) high applicability, (b) high sensitivity, and (c) zero false positive MRD relapses in non-relapsing patients.

X-ray-downregulated nucleophosmin induces abnormal polarization by anchoring to G-actin.

Ionizing radiation poses significant risks to astronauts during deep space exploration. This study investigates the impact of radiation on nucleophosmin (NPM), a protein involved in DNA repair, cell cycle regulation, and proliferation. Using X-rays, a common space radiation, we found that radiation suppresses NPM expression. Knockdown of NPM increases DNA damage after irradiation, disrupts cell cycle distribution and enhances cellular radiosensitivity. Additionally, NPM interacts with globular actin (G-actin), affecting its translocation and centrosome binding during mitosis. These findings provide insights into the role of NPM in cellular processes in responding to radiation. This article enhances our comprehension of radiation-induced genomic instability and provides a foundational platform for prospective investigations within the realm of space radiation and its implications for cancer therapy.

Mutations highly specific for secondary AML are associated with poor outcomes in ELN favorable risk NPM1-mutated AML.

ABSTRACT: Acute myeloid leukemia (AML) is a heterogeneous malignancy with outcomes largely predicted by genetic abnormalities. Mutations of NPM1 are common in AML, occurring in ∼30% of cases, and generally considered a favorable risk factor. Mutations highly specific for secondary AML (sMut) have been shown to confer poor prognosis, but the overall impact of these mutations in the setting of favorable-risk AML defined by mutant NPM1 remains unclear. In this multicenter study of patients with AML (n = 233) with NPM1 mutation at diagnosis, we observed that patients with sMut had worse overall survival (OS) than those without sMut (15.3 vs 43.7 months; P = .002). Importantly, this finding persisted in the European LeukemiaNet (ELN) 2017-defined favorable risk subset (14.7 months vs not reached; P < .0001). Among patients who achieved NPM1 measurable residual disease (MRD) negativity, longer OS was observed in the entire cohort (P = .015) as well as in both the sMut subset (MRD negative: median OS (mOS) 73.9 months vs MRD positive: 12.3 months; P = .0170) and sMut ELN 2017-favorable subset (MRD negative: mOS 27.3 vs MRD positive: 10.5 months; P = .009). Co-occurrence of sMut and mutant NPM1 confers a poor prognosis in AML.

NPM1-Mutated Acute Myeloid Leukemia: Recent Developments and Open Questions.

Somatic mutations in the nucleophosmin (NPM1) gene occur in approximately 30% of de novo acute myeloid leukemias (AMLs) and are relatively enriched in normal karyotype AMLs. Earlier World Health Organization (WHO) classification schema recognized NPM1-mutated AMLs as a unique subtype of AML, while the latest WHO and International Consensus Classification (ICC) now consider NPM1 mutations as AML-defining, albeit at different blast count thresholds. NPM1 mutational load correlates closely with disease status, particularly in the post-therapy setting, and therefore high sensitivity-based methods for detection of the mutant allele have proven useful for minimal/measurable residual disease (MRD) monitoring. MRD status has been conventionally measured by either multiparameter flow cytometry (MFC) and/or molecular diagnostic techniques, although recent data suggest that MFC data may be potentially more challenging to interpret in this AML subtype. Of note, MRD status does not predict patient outcome in all cases, and therefore a deeper understanding of the biological significance of MRD may be required. Recent studies have confirmed that NPM1-mutated cells rely on overexpression of HOX/MEIS1, which is dependent on the presence of the aberrant cytoplasmic localization of mutant NPM1 protein (NPM1c); this biology may explain the promising response to novel agents, including menin inhibitors and second-generation XPO1 inhibitors. In this review, these and other recent developments around NPM1-mutated AML, in addition to open questions warranting further investigation, will be discussed.

Blasts with folded nuclei: A histopathologic finding in myeloid leukemia cutis with NPM1 and FLT3 mutations.

Leukemia cutis is a term used to describe cutaneous manifestations of leukemic infiltration of the skin and portends a poor prognosis. Cutaneous involvement by hematopoietic/lymphoid tumors can occur before, concurrently, or after the initial diagnosis. Early involvement of dermatologists and timely biopsies play a crucial role in achieving a prompt diagnosis. Prior reports of acute myeloid leukemia have revealed a strong association between the cup-like nuclear morphology observed in bone marrow specimens and concurrent mutations of NPM1 and FLT3-ITD. In cutaneous tissue sections of leukemia cutis, folded or indented nuclei may represent the "cup-like" counterpart previously described in bone marrow specimens. Recognizing this morphological feature could aid in identifying this molecular subtype of leukemia cutis. In this study, we present a case of leukemia cutis in a 63-year-old female with AML and NPM1 and FLT3-ITD mutations, demonstrating scattered indented/folded nuclei.

Venetoclax-based low intensity therapy in molecular failure of NPM1-mutated AML.

ABSTRACT: Molecular failure in NPM1-mutated acute myeloid leukemia (AML) inevitably progresses to frank relapse if untreated. Recently published small case series show that venetoclax combined with low-dose cytarabine or azacitidine can reduce or eliminate measurable residual disease (MRD). Here, we report on an international multicenter cohort of 79 patients treated for molecular failure with venetoclax combinations and report an overall molecular response (≥1-log reduction in MRD) in 66 patients (84%) and MRD negativity in 56 (71%). Eighteen of 79 patients (23%) required hospitalization, and no deaths were reported during treatment. Forty-one patients were bridged to allogeneic transplant with no further therapy, and 25 of 41 were MRD negative assessed by reverse transcription quantitative polymerase chain reaction before transplant. Overall survival (OS) for the whole cohort at 2 years was 67%, event-free survival (EFS) was 45%, and in responding patients, there was no difference in survival in those who received a transplant using time-dependent analysis. Presence of FLT3-ITD mutation was associated with a lower response rate (64 vs 91%; P < .01), worse OS (hazard ratio [HR], 2.50; 95% confidence interval [CI], 1.06-5.86; P = .036), and EFS (HR, 1.87; 95% CI, 1.06-3.28; P = .03). Eighteen of 35 patients who did not undergo transplant became MRD negative and stopped treatment after a median of 10 months, with 2-year molecular relapse free survival of 62% from the end of treatment. Venetoclax-based low intensive chemotherapy is a potentially effective treatment for molecular relapse in NPM1-mutated AML, either as a bridge to transplant or as definitive therapy.

The acetylation of STAT3 at K685 attenuates NPM-ALK-induced tumorigenesis.

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), a fusion protein generated by a chromosomal translocation, is a causative gene product of anaplastic large cell lymphoma (ALCL). It induces cell proliferation and tumorigenesis by activating the transcription factor, signal transducer and activator of transcription factor 3 (STAT3). We herein demonstrated that STAT3 underwent acetylation at K685 in a manner that was dependent on the kinase activity of NPM-ALK. To investigate the role of STAT3 acetylation in NPM-ALK-induced oncogenesis, we generated Ba/F3 cells expressing NPM-ALK in which STAT3 was silenced by shRNA, named STAT3-KD cells, and then reconstituted wild-type STAT3 or the STAT3 K685R mutant into these cells. The phosphorylation level of the K685R mutant at Y705 and S727 was significantly higher than that of wild-type STAT3 in STAT3-KD cells. The expression of STAT3 target genes, such as IL-6, Pim1, Pim2, and Socs3, was more strongly induced by the reconstitution of the K685R mutant than wild-type STAT3. In addition, the proliferative ability of STAT3-KD cells reconstituted with the K685R mutant was slightly higher than that of STAT3-KD cells reconstituted with wild-type STAT3. In comparisons with the inoculation of STAT3-KD cells reconstituted with wild-type STAT3, the inoculation of STAT3-KD cells reconstituted with the K685R mutant significantly enhanced tumorigenesis and hepatosplenomegaly in nude mice. Collectively, these results revealed for the first time that the acetylation of STAT3 at K685 attenuated NPM-ALK-induced oncogenesis.