AML Patients Research Articles

Abstract 5991: Improved venetoclax therapy by a novel conjugate with artemisinin by NOXA-mediated reduction of Mcl-1 and cyclin D1 protein in myeloid leukemia cells

Abstract Evasion of apoptosis is crucial for the growth, survival and chemoresistance of myeloid leukemia. The Bcl-2 selective inhibitor venetoclax is the only apoptosis inducer approved for clinical use. Venetoclax in combination with hypomethylating agents or low-dose cytarabine has now become the standard care for elderly AML patients. However, a sizeable fraction of patients are either refractory to venetoclax combination therapy or ultimately relapse. High or induced expression of Mcl-1 and Bcl-xL mediates venetoclax resistance. Previously we reported that artemisinin enhances venetoclax apoptosis induction by degrading Mcl-1 through NOXA induction. We designed a novel conjugate A1 of venetoclax with dihydroartemisinin. A1 shows dual functions of inhibiting Bcl-2 and inducing NOXA. A1 treatment releases Bim from both Bcl-2 and Mcl-1, further degrades Mcl-1 protein, and presents ten-fold stronger apoptotic induction ability in venetoclax insensitive cells. Acquired increase of Mcl-1 protein was observed in venetoclax resistant MOLM-13/VEN cells, which are sensitive to A1-induced apoptosis. In Bcl-xL expressing venetoclax refractory leukemia cells A1 obtains a new mechanism of inhibiting cell cycling by downregulating cyclin D1 through a new NOXA/cyclin D1 cascade, mediated through the endoperoxide moiety of artemisinin and intracellular iron, independent of Bcl-2 inhibition. We reveal a new compound A1 overcoming venetoclax resistance by NOXA-mediated degradation of Mcl-1 and cyclin D1 protein. Citation Format: Jingyi Zhang, Zhenwei Zhang, Samuel Waxman, Linxiang Zhao, Yongkui Jing. Improved venetoclax therapy by a novel conjugate with artemisinin by NOXA-mediated reduction of Mcl-1 and cyclin D1 protein in myeloid leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5991.

Abstract 3626: Day 21 early bone marrow response does not offer high concordance with response bone marrow in the induction chemotherapy setting of FLT3 mutant acute myeloid leukemia

Abstract Purpose: Day 14 early bone marrow biopsies are routinely initiated to determine need for reinduction chemotherapy, but poorly predict true response and risk overtreatment. Day 21 (D21) bone marrow biopsies have been performed in the context of trials utilizing FLT3-targeted therapies in combination with induction chemotherapy (Stone et al. NEJM 2017). However, the utility of D21 bone marrow responses is not well defined. Methods: We retrospectively identified 26 newly diagnosed FLT3 mutant AML patients who underwent induction chemotherapy with midostaurin and Next Generation Sequencing (NGS) of bone marrow aspirate within a week of diagnosis. Results: 19/26 (73%) of patients had both D21 and response bone marrow biopsy. Of the remaining 7 patients, 4 patients did not have D21 bone marrow, 2 died of unrelated complications prior to response bone marrow, and 1 did not have recovery marrow available for assessment. Our cohort included 13 (50%) men with a median age of 57 years (range, 21 - 73 years). All patients had ECOG of 0 - 1. 96% of cases were de novo AML and 81% had normal cytogenetics. FLT3 ITD mutations were detected in 17 (65%) patients with a median FLT3 ITD ratio of 0.305 (range, 0.03 - 1) and median FLT3 VAF of 23.8% (range, 3.2 - 80.6%). 7 patients (26.9%) underwent additional allogeneic stem cell transplant. In the 19 patients evaluable for analysis, 13/13 (100%) patients with blast % ≤ 5 at D21 achieved a complete response (CR) based on recovery marrow. 4/6 (67%) patients with blast % > 5 at D21 which were considered to have residual disease based on pathology review (median blast % 11 (range, 6 - 17%) ultimately achieved a CR. The 2 patients that did not achieve a CR has a blast % of 29% and 9% on D21 marrow. Thus, the positive predictive value of D21 early bone marrow response corresponding with the response bone marrow was only 33% in our patient cohort. Of the 4 patients that did not have D21 marrow but had recovery marrows available for review, the CR rate was 100%. No other significant differences in initial disease characteristics were seen. There were no differences proportion of co-mutations in NPM1, DNMT3A, TP53, IDH2, and IDH1, and higher FLT3 ITD ratio nor FLT3 VAF corresponded with ability to clear D21 bone marrow. Additionally, there were no differences in minimal residual disease (MRD) and overall survival (OS) between the groups. Conclusions: Our study suggests early bone marrow response in the context of FLT3-mutant disease is not dependent on inherent disease characteristics and does not correspond to overall response to targeted induction chemotherapy. The utility of these marrows in is this population needs to be studied further in a larger cohort to better understand the clinical necessity to avoid unnecessary cost/procedures to patients and even more importantly unnecessary reinductions. Citation Format: Vincent Lok, Su Bin Hahn, Nikesh N. Shah, Daniel A. Kerr, Ivan M. Borrello, Eduardo M. Sotomayor, David M. Swoboda. Day 21 early bone marrow response does not offer high concordance with response bone marrow in the induction chemotherapy setting of FLT3 mutant acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3626.

LSP1 promotes the progression of acute myelogenous leukemia by regulating KSR/ERK signaling pathway and cell migration

ABSTRACT We aimed to investigate the role and mechanism of LSP1 in the progression of acute myelogenous leukemia. In this study, we established shLSP1 cell line to analyze the function of LSP1 in AML. We observed high expression of LSP1 in AML patients, whereas it showed no expression in normal adults. Furthermore, we found that LSP1 expression was associated with disease prognosis. Our results indicate that LSP1 plays a crucial role in mediating proliferation and survival of leukemia cells through the KSR/ERK signaling pathway. Additionally, LSP1 promotes cell chemotaxis and homing by enhancing cell adhesion and migration. We also discovered that LSP1 confers chemotactic ability to leukemia cells in vivo. Finally, our study identified 12 genes related to LSP1 in AML, which indicated poor survival outcome in AML patients and were enriched in Ras and cell adhesion signaling pathways. Our results revealed that the overexpression of LSP1 is related to the activation of the KSR/ERK signaling pathway, as well as cell adhesion and migration in AML patients. Reducing LSP1 expression impair AML progression, suggesting that LSP1 may serve as a potential drug therapy target for more effective treatment of AML.

Uncovering the cellular and omics characteristics of natural killer cells in the bone marrow microenvironment of patients with acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is a highly heterogeneous hematologic malignancy and the most frequently acute leukemia of stem cell precursors and the myeloid derivatives in adult. Longitudinal studies have indicated the therapeutic landscape and drug resistance for patients with AML are still intractable, which largely attribute to the deficiency of detailed information upon the pathogenesis.MethodsIn this study, we compared the cellular phenotype of resident NK cells (rAML-NKs, rHD-NKs) and expanded NK cells (eAML-NKs, eHD-NKs) from bone marrow of AML patients (AML) and healthy donors (HD). Then, we took advantage of the co-culture strategy for the evaluation of the in vitro cytotoxicity of NK cells upon diverse tumor cell lines (e.g., K562, Nalm6, U937). With the aid of RNA-sequencing (RNA-SEQ) and bioinformatics analyses (e.g., GOBP analysis, KEGG analysis, GSEA, volcano plot), we verified the similarities and differences of the omics features between eAML-NKs and eHD-NKs.ResultsHerein, we verified the sharp decline in the content of total resident NK cells (CD3−CD56+) in rAML-NKs compared to rHD-NKs. Differ from the expanded eHD-NKs, eAML-NKs revealed decline in diverse NK cell subsets (NKG2D+, CD25+, NKp44+, NKp46+) and alterations in cellular vitality but conservations in cytotoxicity. According to transcriptomic analysis, AML-NKs and HD-NKs showed multifaceted distinctions in gene expression profiling and genetic variations.ConclusionsCollectively, our data revealed the variations in the cytobiological and transcriptomic features between AML-NKs and HD-NKs in bone marrow environment. Our findings would benefit the further development of novel biomarkers for AML diagnosis and NK cell-based cytotherapy in future.

ABT199/venetoclax synergism with thiotepa enhances the cytotoxicity of fludarabine, cladribine and busulfan in AML cells.

ABT199/venetoclax, an inhibitor of the pro-survival BCL-2 protein, has improved AML treatment. Its efficacy in hematopoietic stem cell transplantation (HSCT), when combined with other chemotherapeutic drugs, has not been thoroughly investigated. The present study demonstrates the synergistic cytotoxicity of ABT199/venetoclax with the DNA alkylator thiotepa (Thio) in AML cells. Cleavage of Caspase 3, PARP1 and HSP90, as well as increased Annexin V positivity, suggest potent activation of apoptosis by this two-drug combination; increased levels of γ-H2AX, P-CHK1 (S317), P-CHK2 (S19) and P-SMC1 (S957) indicate an enhanced DNA damage response. Likewise, the increased level of P-SAPK/JNK (T183/Y185) and decreased P-PI3Kp85 (Y458) suggest enhanced activation of stress signaling pathways. These molecular readouts were synergistically enhanced when ABT199/venetoclax and Thio were combined with fludarabine, cladribine and busulfan. The five-drug combination decreased the levels of BCL-2, BCL-xL and MCL-1, suggesting its potential clinical relevance in overcoming ABT199/venetoclax resistance. Moreover, this combination is active against P53-negative and FLT3-ITD-positive cell lines. Enhanced activation of apoptosis was observed in leukemia patient-derived cell samples exposed to the five-drug combination, suggesting a clinical relevance. The results provide a rationale for clinical trials using these two- and five-drug combinations as part of a conditioning regimen for AML patients undergoing HSCT.

C/EBPα-p30 confers AML cell susceptibility to the terminal unfolded protein response and resistance to Venetoclax by activating DDIT3 transcription

BackgroundAcute myeloid leukemia (AML) with biallelic (CEBPAbi) as well as single mutations located in the bZIP region is associated with a favorable prognosis, but the underlying mechanisms are still unclear. Here, we propose that two isoforms of C/EBPα regulate DNA damage-inducible transcript 3 (DDIT3) transcription in AML cells corporately, leading to altered susceptibility to endoplasmic reticulum (ER) stress and related drugs.MethodsHuman AML cell lines and murine myeloid precursor cell line 32Dcl3 cells were infected with recombinant lentiviruses to knock down CEBPA expression or over-express the two isoforms of C/EBPα. Quantitative real-time PCR and western immunoblotting were employed to determine gene expression levels. Cell apoptosis rates were assessed by flow cytometry. CFU assays were utilized to evaluate the differentiation potential of 32Dcl3 cells. Luciferase reporter analysis, ChIP-seq and ChIP-qPCR were used to validate the transcriptional regulatory ability and affinity of each C/EBPα isoform to specific sites at DDIT3 promoter. Finally, an AML xenograft model was generated to evaluate the in vivo therapeutic effect of agents.ResultsWe found a negative correlation between CEBPA expression and DDIT3 levels in AML cells. After knockdown of CEBPA, DDIT3 expression was upregulated, resulting in increased apoptotic rate of AML cells induced by ER stress. Cebpa knockdown in mouse 32Dcl3 cells also led to impaired cell viability due to upregulation of Ddit3, thereby preventing leukemogenesis since their differentiation was blocked. Then we discovered that the two isoforms of C/EBPα regulate DDIT3 transcription in the opposite way. C/EBPα-p30 upregulated DDIT3 transcription when C/EBPα-p42 downregulated it instead. Both isoforms directly bound to the promoter region of DDIT3. However, C/EBPα-p30 has a unique binding site with stronger affinity than C/EBPα-p42. These findings indicated that balance of two isoforms of C/EBPα maintains protein homeostasis and surveil leukemia, and at least partially explained why AML cells with disrupted C/EBPα-p42 and/or overexpressed C/EBPα-p30 exhibit better response to chemotherapy stress. Additionally, we found that a low C/EBPα p42/p30 ratio induces resistance in AML cells to the BCL2 inhibitor venetoclax since BCL2 is a major target of DDIT3. This resistance can be overcome by combining ER stress inducers, such as tunicamycin and sorafenib in vitro and in vivo.ConclusionOur results indicate that AML patients with a low C/EBPα p42/p30 ratio (e.g., CEBPAbi) may not benefit from monotherapy with BCL2 inhibitors. However, this issue can be resolved by combining ER stress inducers.

Venetoclax Resistance in Acute Myeloid Leukemia.

Venetoclax is a BH3-mimetics agent interacting with the anti-apoptotic protein BCL2, facilitating cytochrome c release from mitochondria, subsequent caspases activation, and cell death. Venetoclax combined with azacitidine (VEN-AZA) has become a new standard treatment for AML patients unfit for intensive chemotherapy. In the phase III VIALE-A study, VEN-AZA showed a 65% overall response rate and 14.7 months overall survival in comparison with 22% and 8 months in the azacitidine monotherapy control arm. Despite these promising results, relapses and primary resistance to venetoclax are frequent and remain an unmet clinical need. Clinical and preclinical studies have been conducted to identify factors driving resistance. Among them, the most documented are molecular alterations including IDH, FLT3, TP53, and the newly described BAX mutations. Several non-genetic factors are also described such as metabolic plasticity, changes in anti-apoptotic protein expression, and dependencies, as well as monocytic differentiation status. Strategies to overcome venetoclax resistance are being developed in clinical trials, including triplet therapies with targeted agents targeting IDH, FLT3, as well as the recently developed menin inhibitors or immunotherapies such as antibody-drug conjugated or monoclonal antibodies. A better understanding of the molecular factors driving venetoclax resistance by single-cell analyses will help the discovery of new therapeutic strategies in the future.

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia.

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Abstract P25: Identification of biological components and novel clinical subsets of NPM1-mutated AML using an integrated, multi-omics approach

Abstract P25: Identification of biological components and novel clinical subsets of <i>NPM1</i>-mutated AML using an integrated, multi-omics approach

Mental Health Issues Among AML Patients on Venetoclax

Mental Health Issues Among AML Patients on Venetoclax

Olutasidenib as a Breakthrough for R/R mIDH1 AML Patients

Olutasidenib as a Breakthrough for R/R mIDH1 AML Patients

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

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. In this retrospective study, we compared five classifiers: ELN 2017, ELN 2022, ALFA classifier, Papaemmanuil etal. classifier, and Lindsley etal. 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%). 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. 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.

Quantifying NPM1 MRD in AML patients prior to allogeneic stem cell transplantation: Where to draw the line?

Quantifying NPM1 MRD in AML patients prior to allogeneic stem cell transplantation: Where to draw the line?

White blood cell count nadir to zero following intensive chemotherapy as a predictive factor for patients with acute myeloid leukemia

Predictors for response to intensive therapy in AML have focused on baseline factors: percent leukemic blasts in marrow, cytogenetic/molecular genetic abnormalities, and presence of secondary AML. Non-baseline dynamic factors, occurring after induction but before response, may be useful for decisions related to salvage chemotherapy. We hypothesized white blood cell (WBC) count nadir after induction may be a real time indicator of treatment efficacy. We also examined whether time to stem cell transplant (SCT) or baseline molecular genetic abnormalities are associated with a low nadir. Data showed WBC nadir = 0 was a negative predictor for response to intensive induction and was correlated with reduced overall survival and progression free survival. Patients with WBC nadir = 0 did not have a significantly longer time to SCT, and none of the mutations increased the likelihood of reaching WBC nadir = 0. WBC nadir may be a useful real-time monitor in AML patients receiving intensive induction chemotherapy.

Super enhancer related gene ANP32B promotes the proliferation of acute myeloid leukemia by enhancing MYC through histone acetylation

BackgroundAcute myeloid leukemia (AML) is a malignancy of the hematopoietic system, and childhood AML accounts for about 20% of pediatric leukemia. ANP32B, an important nuclear protein associated with proliferation, has been found to regulate hematopoiesis and CML leukemogenesis by inhibiting p53 activity. However, recent study suggests that ANP32B exerts a suppressive effect on B-cell acute lymphoblastic leukemia (ALL) in mice by activating PU.1. Nevertheless, the precise underlying mechanism of ANP32B in AML remains elusive.ResultsSuper enhancer related gene ANP32B was significantly upregulated in AML patients. The expression of ANP32B exhibited a negative correlation with overall survival. Knocking down ANP32B suppressed the proliferation of AML cell lines MV4-11 and Kasumi-1, along with downregulation of C-MYC expression. Additionally, it led to a significant decrease in H3K27ac levels in AML cell lines. In vivo experiments further demonstrated that ANP32B knockdown effectively inhibited tumor growth.ConclusionsANP32B plays a significant role in promoting tumor proliferation in AML. The downregulation of ANP32B induces cell cycle arrest and promotes apoptosis in AML cell lines. Mechanistic analysis suggests that ANP32B may epigenetically regulate the expression of MYC through histone H3K27 acetylation. ANP32B could serve as a prognostic biomarker and potential therapeutic target for AML patients.

Hypomethylating agents plus venetoclax compared with intensive induction chemotherapy regimens in molecularly defined secondary AML.

Molecularly defined secondary acute myeloid leukemia is associated with a prior myeloid neoplasm and confers a worse prognosis. We compared outcomes of molecularly defined secondary AML patients (n = 395) treated with daunorubicin and cytarabine (7 + 3, n = 167), liposomal daunorubicin and cytarabine (CPX-351, n = 66) or hypomethylating agents (HMA) + venetoclax (VEN) (n = 162). Median overall survival (OS) was comparable between treatment groups among patients aged >60 years. In a multivariable model HMA + VEN vs. 7 + 3 was associated with better OS (hazard ratio [HR] 0.64 [95% confidence interval (CI) 0.42-0.98, p = 0.041]), whereas CPX-351 vs. 7 + 3 was not (HR 0.79 [CI 95% 0.50-1.25, p = 0.31]). Allogeneic hematopoietic stem cell transplantation, BCOR and IDH mutations were associated with improved OS; older age, prior myeloid disease, NRAS/KRAS mutations, EZH2 mutation, and monosomal karyotype were associated with worse OS. When analyzed in each treatment separately, the IDH co-mutations benefit was seen with 7 + 3 and the detrimental effect of NRAS/KRAS co-mutations with HMA + VEN and CPX-351. In pairwise comparisons adjusted for age, HMA + VEN was associated with improved OS vs. 7 + 3 in patients with SF3B1 mutation and improved OS vs. CPX-351 in those with RNAsplicing factormutations. In molecularly defined secondary AML treatment with HMA + VEN might be preferred but could further be guided by co-mutations.

Significance of OCT3/4 and SOX2 antigens expression by leukemic blast cells in adult acute leukemia

ObjectiveThis study aimed to address the prognostic impact of SOX2 and OCT3/4 expression on adult acute leukemia patients’ outcomes.MethodsSOX2 and OCT3/4 expression by blast cells were evaluated by flow cytometry in 80 acute leukemia patients and 8 healthy controls.ResultsBaseline SOX2 and OCT3/4 expression were significantly higher in both ALL (P = < 0.001, P = 0.005 respectively) and AML patients (P < 0.001, P = 0.003 respectively) as compared to control, and decline at complete remission (CR) and elevated again at relapse. High SOX2 and OCT3/4 levels were significantly correlated with the presence of adverse risk stratification parameters.ConclusionOur findings indicated that both SOX2 and OCT3/4 could serve as biomarkers that could improve risk stratification of acute leukemia patients. Also, both SOX2 and OCT3/4 might be a therapeutic target, especially in resistant acute leukemia.

Cancer-Stem-Cell Phenotype-Guided Discovery of a Microbiota-Inspired Synthetic Compound Targeting NPM1 for Leukemia.

The human microbiota plays an important role in human health and disease, through the secretion of metabolites that regulate key biological functions. We propose that microbiota metabolites represent an unexplored chemical space of small drug-like molecules in the search of new hits for drug discovery. Here, we describe the generation of a set of complex chemotypes inspired on selected microbiota metabolites, which have been synthesized using asymmetric organocatalytic reactions. Following a primary screening in CSC models, we identified the novel compound UCM-13369 (4b) whose cytotoxicity was mediated by NPM1. This protein is one of the most frequent mutations of AML, and NPM1-mutated AML is recognized by the WHO as a distinct hematopoietic malignancy. UCM-13369 inhibits NPM1 expression, downregulates the pathway associated with mutant NPM1 C+, and specifically recognizes the C-end DNA-binding domain of NPM1 C+, avoiding the nucleus-cytoplasm translocation involved in the AML tumorological process. The new NPM1 inhibitor triggers apoptosis in AML cell lines and primary cells from AML patients and reduces tumor infiltration in a mouse model of AML with NPM1 C+ mutation. The disclosed phenotype-guided discovery of UCM-13369, a novel small molecule inspired on microbiota metabolites, confirms that CSC death induced by NPM1 inhibition represents a promising therapeutic opportunity for NPM1-mutated AML, a high-mortality disease.

Clinical Characteristics of Patients with Hematologic Malignancies and Invasive Aspergillosis: A Cross-sectional Clinical Report from Iran

Background: The incidence of invasive aspergillosis (IA) has significantly increased in recent decades. In patients with hematologic malignancies (HM), IA is associated with higher mortality rates. Objectives: This study aimed to assess the clinical features of IA in patients with HM. Methods: In this retrospective study, we used the hospital information system (HIS) database to extract clinical and paraclinical characteristics of patients with various HMs who received a diagnosis of probable or proven IA during their hospitalization at Imam Khomeini Hospital Complex in Tehran, Iran, between March 2018 and March 2022. Results: After evaluating 350 patients with HM, 51 patients with IA (14.6%) were identified, of whom 40 cases (78.4%) were probable and 11 (21.6%) were proven. Among these, 34 individuals (66.7%) were male. The most common symptoms were fever (n = 23, 62.7%), cough (n = 20, 39.2%), and fever that did not respond to antibiotic therapy (n = 16, 31.4%). The most prevalent malignancies were AML (n = 28, 54.9%), ALL (n = 16, 31.4%), and lymphoma (n = 7, 13.7%). Out of the 51 patients with HM and IA, 48 (94.1%) had abnormal findings on chest CT scans, with the majority (n = 31, 72.1%) showing a nodule with a halo sign. Aspergillus flavus (n = 19/24, 79.2%) was the most commonly isolated species. Initially, patients received liposomal amphotericin B or caspofungin as empiric antifungal therapy, which was then switched to voriconazole once the diagnosis of IA was probable or proven. Eight patients (15.6%) died. Conclusions: Patients with HM presenting with fever and cough should undergo close monitoring for IA. A higher incidence of IA is observed in AML patients, and voriconazole could be considered as antifungal prophylaxis in HM patients. A. flavus is likely the most frequent cause of IA in Iranian patients with HM.

PHF6 loss reduces leukemia stem cell activity in an acute myeloid leukemia mouse model

Acute myeloid leukemia (AML) is a malignant hematologic disease caused by gene mutations and genomic rearrangements in hematologic progenitors. The PHF6 (PHD finger protein 6) gene is highly conserved and located on the X chromosome in humans and mice. We found that PHF6 was highly expressed in AML cells with MLL rearrangement and was related to the shortened survival time of AML patients. In our study, we knocked out the Phf6 gene at different disease stages in the AML mice model. Moreover, we knocked down PHF6 by shRNA in two AML cell lines and examined the cell growth, apoptosis, and cell cycle. We found that PHF6 deletion significantly inhibited the proliferation of leukemic cells and prolonged the survival time of AML mice. Interestingly, the deletion of PHF6 at a later stage of the disease displayed a better anti-leukemia effect. The expressions of genes related to cell differentiation were increased, while genes that inhibit cell differentiation were decreased with PHF6 knockout. It is very important to analyze the maintenance role of PHF6 in AML, which is different from its tumor-suppressing function in T-cell acute lymphoblastic leukemia (T-ALL). Our study showed that inhibiting PHF6 expression may be a potential therapeutic strategy targeting AML patients.