Be aware of the X: BCOR mutations in myeloid neoplasms

Not available.

Survival improvement of patients with FLT3 mutated acute myeloid leukemia: results from a prospective 9 years cohort

Midostaurin added to intensive chemotherapy is the standard of care for acute myeloid leukemia (AML) with FLT3 mutations (FLT3mut). We analyzed the impact of midostaurin in 227 FLT3mut-AML patients included in the AML-12 prospective trial for fit patients ≤70 years (#NCT04687098). Patients were divided into an early (2012-2015) and late (2016-2020) cohorts. They were uniformly treated except for the addition of midostaurin in 71% of late group patients. No differences were observed in response rates or the number of allotransplants between groups. Outcome was improved in the late period: 2-year relapse incidence decreased from 42% vs 29% in early vs late group (p = 0.024) and 2-year overall survival (OS) improved from 47% vs 61% (p = 0.042), respectively. The effect of midostaurin was evident in NPM1mut patients (n = 151), with 2-yr OS of 72% (exposed) vs 50% (naive) patients (p = 0.011) and mitigated FLT3-ITD allelic ratio prognostic value: 2-yr OS with midostaurin was 85% and 58% in low and high ratio patients (p = 0.049) vs 67% and 39% in naive patients (p = 0.005). In the wild-type NPM1 subset (n = 75), we did not observe significant differences between both study periods. In conclusion, this study highlights the improved outcome of FLT3mut AML fit patients with the incorporation of midostaurin.

5'-nucleotidase, cytosolic ii genotype and clinical outcome in patients with acute myeloid leukemia with intermediate-risk cytogenetics

Acute myeloid leukemia (AML) is a complex disease, and its treatment needs to be adjusted to the risk, which is conferred by cytogenetics and molecular markers. Cytarabine is the main drug to treat AML, and it has been suggested that the genotype of cytarabine metabolizing enzymes may have a prognostic relevance in AML. Here we report the association between the 5'-nucleotidase, cytosolic II (NT5C2) rs10883841, cytidine deaminase (CDA) rs2072671 and rs532545 genotypes and the clinical outcome of 477 intermediate-risk cytogenetic AML patients receiving cytarabine-based chemotherapy. Patients younger than 50 years old with the NT5C2 rs10883841 AA genotype had lower overall survival (OS) (p: 0.003; HR 2.16, 95%CI 1.29 - 3.61) and lower disease-free survival (DFS) (p: 0.002; HR 2.45, 95%CI 1.41 - 4.27), associated to a higher relapse incidence (p: 0.010; HR 2.23, 95%CI 1.21 - 4.12). Interestingly, subgroup analysis showed that the negative effect of the NT5C2 rs10883841 AA genotype was detected in all subgroups except in patients with nucleophosmin mutation without high ratio FLT-3 internal tandem duplication. CDA polymorphisms were associated with the complete remission rate after induction chemotherapy, without influencing OS. Further studies are warranted to determine whether this pharmacogenomic approach may be helpful to individualize AML treatment.

The evolution of hematopoietic cells under cancer therapy

Chemotherapies may increase mutagenesis of healthy cells and change the selective pressures in tissues, thus influencing their evolution. However, their contributions to the mutation burden and clonal expansions of healthy somatic tissues are not clear. Here, exploiting the mutational footprint of some chemotherapies, we explore their influence on the evolution of hematopoietic cells. Cells of Acute Myeloid Leukemia (AML) secondary to treatment with platinum-based drugs show the mutational footprint of these drugs, indicating that non-malignant blood cells receive chemotherapy mutations. No trace of the 5-fluorouracil (5FU) mutational signature is found in AMLs secondary to exposure to 5FU, suggesting that cells establishing the leukemia could be quiescent during treatment. Using the platinum-based mutational signature as a barcode, we determine that the clonal expansion originating the secondary AMLs begins after the start of the cytotoxic treatment. Its absence in clonal hematopoiesis cases is consistent with the start of the clonal expansion predating the exposure to platinum-based drugs.

Venetoclax in relapsed/refractory blastic plasmacytoid dendritic cell neoplasm with central nervous system involvement: a case report and review of the literature

BACKGROUND

We describe a patient with blastic plasmacytoid dendritic cell neoplasm with central nervous system involvement and the outcome of venetoclax use in this setting.

CASE PRESENTATION

A 54-year-old Caucasian male was referred to the Haematology Unit with an enlarged inguinal lymph node which was diagnostic of a blastic plasmacytoid dendritic cell neoplasm. The staging revealed disseminated disease (skin, visceral, lymph nodes, and bone marrow). He received chemotherapy with an acute myeloid leukaemia-like regime. Afterwards, he underwent allogeneic haematopoietic stem cell transplantation, though it was not successful, showing a relapse 14 months later with hepatic and central nervous system dissemination. Intrathecal chemotherapy was administered, and venetoclax (anti-bcl2 agent) was started in an off-label indication based on most recent literature. The disease halted its course for 3 months. In the end, the patient's disease progressed and so he succumbed due to infectious complications.

CONCLUSIONS

Venetoclax monotherapy seems not enough to control the disease progression under CNS involvement and other treatments should be investigated.

Bone marrow fibrosis, sequence variant of asxl1, and Sjögren syndrome: A case report

Only proven pathogenic mutations associated with myeloid neoplasms are key to establish the clonal nature of the bone marrow fibrosis. In cases with genetic variants of uncertain meaning, the clinical picture may be required to rule out secondary causes.

Acute myeloid leukemia with NPM1 mutation and favorable European LeukemiaNet category: outcome after preemptive intervention based on measurable residual disease

In the European LeukemiaNet favourable risk category, allogeneic haematopoietic stem cell transplantation (alloSCT) is not indicated in first complete remission for patients with acute myeloid leukaemia (AML) with NPM1 mutations (ELNfav NPM1 AML), although a proportion of these patients will relapse. Given the prognostic importance of measurable residual disease (MRD), CETLAM-12 considered a pre-emptive intervention in patients with molecular failure (MF). We analyzed 110 ELNfav NPM1 AML patients achieving complete remission (CR) after induction chemotherapy. Two-year cumulative incidence of relapse (CIR), overall survival (OS) and leukaemia-free survival (LFS) were 17%, 81·5% and 82%, respectively. Forty-six patients required additional therapy for MF (n = 33) or haematological relapse (HemR; n = 13), resulting in a molecular LFS (molLFS) and a cumulative incidence of MF at two years of 61% and 38% respectively. Two-year OS for these 46 patients was 66%, with a different outcome between patients with MF (86%) and HemR (42%) (P = 0·002). Quantitative NPM1 detection at different timepoints was predictive of molLFS; an MRD ratio (NPM1mut/ABL1 × 100) cut-off of 0·05 after first consolidation identified two cohorts with a two-year molLFS of 77% and 40% for patients below and above 0·05, respectively. In conclusion, MRD-based pre-emptive intervention resulted in a favourable outcome for ELNfav NPM1 AML patients.

UGT1A1 genotype influences clinical outcome in patients with intermediate-risk acute myeloid leukemia treated with cytarabine-based chemotherapy

The treatment of acute myeloid leukemia (AML) is adjusted according to cytogenetic risk factors and molecular markers. Cytarabine remains the main drug to treat AML, and several studies have explored the prognostic relevance of the genotype of cytarabine metabolizing enzymes in AML. Glucuronidation has been identified to be relevant in the cytarabine clearance, but there are still few data concerning the clinical impact of genetic polymorphisms known to condition the activity of UDP-glucuronosyl transferases in AML patients. Here we report the association between the UGT1A1 rs8175347 genotype and the clinical outcome of 455 intermediate-risk cytogenetic AML patients receiving cytarabine-based chemotherapy. Patients with the UGT1A1*28 homozygous variant (associated to a lower UGT1A1 activity) had a lower overall survival (OS) (25.8% vs. 45.5%; p: 0.004). Multivariate analysis confirmed this association (p: 0.008; HR: 1.79; 95% CI: 1.16-2.76). Subgroup analysis showed the negative effect of the UGT1A1*28 homozygous genotype on OS in women (14.8% vs. 52.7%; p: 0.001) but not in men. This lower OS was associated with longer neutropenia after consolidation chemotherapy and with higher mortality without previous relapse, suggesting an association between a low glucuronidation activity and mortal toxic events.

Application of a digital PCR method for WT1 to myeloid neoplasms in CR and deep ELN WT1 molecular response (< 10 copies)

Bone marrow WT1 mRNA levels assessed by the ELN method are useful to establish prognostic correlations in myeloid malignancies treated with chemotherapy or hematopoietic stem cell transplantation (HCT). Those patients with WT1 levels below ten copies have a good outcome. However, some of these patients relapse. To further characterize this group of cases, we applied a new and sensitive digital (ddPCR) WT1 method. A consecutive series of 49 patients with treated myeloid malignancies and with an ELN WT1 quantitation of < 10 copies were included in the study. All cases (47 AML and 2 MDS) have received intensive chemotherapy or HCT. One to four micrograms of total RNA were retrotranscribed to obtain ≥ 10,000 ABL1 copies using the ELN protocol. Only those cases with a good quality cDNA were used in the ddPCR WT1 test. The ddPCR Gene Expression WT1 Assay of Bio-Rad© was used to perform the PCR amplification, and the microdroplets were quantified in the Bio-Rad's QX200 droplet reader. Eighteen patients showed a negative WT1 ddPCR assay (0 copies/μl), whereas 31 cases were positive (results ranged from 1 to 15.2 copies/μl). Survival analysis showed statistically significant differences in terms of OS between both groups, 83 ± 8% vs. 46 ± 9% (p = 0.024). A statistically significant correlation was also found between ddPCRWT1 results and CD123+ cell number detected by flow cytometry (p = 0.024). Larger series of patients tested with the current ddPCRWT1 method will solve whether it could be used to stratify patients with myeloid malignancies achieving deep WT1 molecular response (< 10 copies).

Measurable Residual Disease Assessed by Flow-Cytometry Is a Stable Prognostic Factor for Pediatric T-Cell Acute Lymphoblastic Leukemia in Consecutive SEHOP Protocols Whereas the Impact of Oncogenetics Depends on Treatment

Robust and applicable risk-stratifying genetic factors at diagnosis in pediatric T-cell acute lymphoblastic leukemia (T-ALL) are still lacking, and most protocols rely on measurable residual disease (MRD) assessment. In our study, we aimed to analyze the impact of NOTCH1, FBXW7, PTEN, and RAS mutations, the measurable residual disease (MRD) levels assessed by flow cytometry (FCM-MRD) and other reported risk factors in a Spanish cohort of pediatric T-ALL patients. We included 199 patients treated with SEHOP and PETHEMA consecutive protocols from 1998 to 2019. We observed a better outcome of patients included in the newest SEHOP-PETHEMA-2013 protocol compared to the previous SHOP-2005 cohort. FCM-MRD significantly predicted outcome in both protocols, but the impact at early and late time points differed between protocols. The impact of FCM-MRD at late time points was more evident in SEHOP-PETHEMA 2013, whereas in SHOP-2005 FCM-MRD was predictive of outcome at early time points. Genetics impact was different in SHOP-2005 and SEHOP-PETHEMA-2013 cohorts: NOTCH1 mutations impacted on overall survival only in the SEHOP-PETHEMA-2013 cohort, whereas homozygous deletions of CDKN2A/B had a significantly higher CIR in SHOP-2005 patients. We applied the clinical classification combining oncogenetics, WBC count and MRD levels at the end of induction as previously reported by the FRALLE group. Using this score, we identified different subgroups of patients with statistically different outcome in both Spanish cohorts. In SHOP-2005, the FRALLE classifier identified a subgroup of high-risk patients with poorer survival. In the newest protocol SEHOP-PETHEMA-2013, a very low-risk group of patients with excellent outcome and no relapses was detected, with borderline significance. Overall, FCM-MRD, WBC count and oncogenetics may refine the risk-stratification, helping to design tailored approaches for pediatric T-ALL patients.

Ultrastructural, cytogenetic, and molecular findings in mast cell leukemia: Case report

We report a de novo aleukemic form of MCL with a complex monosomic karyotype with LOH for multiple chromosomes and TP53 mutation. Additionally, whereas D816V KIT was not found, the c-Kit transmembrane domain p.M541L variant was detected which is the most common SNP of KIT gene in humans with controversial pathogenic role. In these cases, it is crucial to perform a rapid broad molecular study for an accurate diagnosis which could help to initiate targeted therapy.

A novel deep targeted sequencing method for minimal residual disease monitoring in acute myeloid leukemia

A high proportion of patients with acute myeloid leukemia who achieve minimal residual disease negative status ultimately relapse because a fraction of pathological clones remains undetected by standard methods. We designed and validated a high-throughput sequencing method for minimal residual disease assessment of cell clonotypes with mutations of NPM1, IDH1/2 and/or FLT3-single nucleotide variants. For clinical validation, 106 follow-up samples from 63 patients in complete remission were studied by sequencing, evaluating the level of mutations detected at diagnosis. The predictive value of minimal residual disease status by sequencing, multiparameter flow cytometry, or quantitative polymerase chain reaction analysis was determined by survival analysis. The sequencing method achieved a sensitivity of 10⁻⁴ for single nucleotide variants and 10⁻⁵ for insertions/deletions and could be used in acute myeloid leukemia patients who carry any mutation (86% in our diagnostic data set). Sequencing–determined minimal residual disease positive status was associated with lower disease-free survival (hazard ratio 3.4, P=0.005) and lower overall survival (hazard ratio 4.2, P<0.001). Multivariate analysis showed that minimal residual disease positive status determined by sequencing was an independent factor associated with risk of death (hazard ratio 4.54, P=0.005) and the only independent factor conferring risk of relapse (hazard ratio 3.76, P=0.012). This sequencing-based method simplifies and standardizes minimal residual disease evaluation, with high applicability in acute myeloid leukemia. It is also an improvement upon flow cytometry- and quantitative polymerase chain reaction-based prediction of outcomes of patients with acute myeloid leukemia and could be incorporated in clinical settings and clinical trials.

Frequency and clinical impact of CDKN2A/ARF/CDKN2B gene deletions as assessed by in-depth genetic analyses in adult T cell acute lymphoblastic leukemia

Recurrent deletions of the CDKN2A/ARF/CDKN2B genes encoded at chromosome 9p21 have been described in both pediatric and adult acute lymphoblastic leukemia (ALL), but their prognostic value remains controversial, with limited data on adult T-ALL. Here, we investigated the presence of homozygous and heterozygous deletions of the CDKN2A/ARF and CDKN2B genes in 64 adult T-ALL patients enrolled in two consecutive trials from the Spanish PETHEMA group. Alterations in CDKN2A/ARF/CDKN2B were detected in 35/64 patients (55%). Most of them consisted of 9p21 losses involving homozygous deletions of the CDKNA/ARF gene (26/64), as confirmed by single nucleotide polymorphism (SNP) arrays and interphase fluorescence in situ hybridization (iFISH). Deletions involving the CDKN2A/ARF/CDKN2B locus correlated with a higher frequency of cortical T cell phenotype and a better clearance of minimal residual disease (MRD) after induction therapy. Moreover, the combination of an altered copy-number-value (CNV) involving the CDKN2A/ARF/CDKN2B gene locus and undetectable MRD (≤ 0.01%) values allowed the identification of a subset of T-ALL with better overall survival in the absence of hematopoietic stem cell transplantation.

A 4-gene expression prognostic signature might guide post-remission therapy in patients with intermediate-risk cytogenetic acute myeloid leukemia

In intermediate-risk cytogenetic acute myeloid leukemia (IRC-AML) patients, novel biomarkers to guide post-remission therapy are needed. We analyzed with high-density arrays 40 IRC-AML patients who received a non-allogeneic hematopoietic stem-cell transplantation-based post-remission therapy, and identified a signature that correlated with early relapse. Subsequently, we analyzed selected 187 genes in 49 additional IRC-AML patients by RT-PCR. BAALC, MN1, SPARC and HOPX overexpression correlated to refractoriness. BAALC or ALDH2 overexpression correlated to shorter overall survival (OS) (5-year OS: 33 ± 8.6% vs. 73.7 ± 10.1%, p = .006; 32 ± 9.3% vs. 66.4 ± 9.7%, p = .016), whereas GPR44 or TP53INP1 overexpression correlated to longer survival (5-year OS: 66.7 ± 10.3% vs. 35.4 ± 9.1%, p = .04; 58.3 ± 8.2% vs. 23.1 ± 11.7%, p = .029). A risk-score combining these four genes expression distinguished low-risk and high-risk patients (5-year OS: 79 ± 9% vs. 30 ± 8%, respectively; p = .001) in our cohort and in an independent set of patients from a public repository. Our 4-gene signature may add prognostic information and guide post-remission treatment in IRC-AML patients.

Emetine induces chemosensitivity and reduces clonogenicity of acute myeloid leukemia cells

Acute myeloid leukemia (AML) is an hematologic neoplasia characterized by the accumulation of transformed immature myeloid cells in bone marrow. Although the response rate to induction therapy is high, survival rate 5-year after diagnosis is still low, highlighting the necessity of new novel agents. To identify agents with the capability to abolish the self-renewal capacity of AML blasts, an in silico screening was performed to search for small molecules that induce terminal differentiation. Emetine, a hit compound, was validated for its anti-leukemic effect in vitro, ex vivo and in vivo. Emetine, a second-line anti-protozoa drug, differentially reduced cell viability and clonogenic capacity of AML primary patient samples, sparing healthy blood cells. Emetine treatment markedly reduced AML burden in bone marrow of xenotransplanted mice and decreased self-renewal capacity of the remaining engrafted AML cells. Emetine also synergized with commonly used chemotherapeutic agents such as ara-C. At a molecular level, emetine treatment was followed by a reduction in HIF-1α protein levels. This study validated the anti-leukemiceffect of emetine in AML cell lines, a group of diverse AML primary samples, and in a human AML-transplanted murine model, sparing healthy blood cells. The selective anti-leukemic effect of emetine together with the safety of the dose range required to exert this effect support the development of this agent in clinical practice.

Copy number profiling of adult relapsed B-cell precursor acute lymphoblastic leukemia reveals potential leukemia progression mechanisms

The outcome of relapsed adult acute lymphoblastic leukemia (ALL) remains dismal despite new therapeutic approaches. Previous studies analyzing relapse samples have shown a high degree of heterogeneity regarding gene alterations without an evident relapse signature. Bone marrow or peripheral blood samples from 31 adult B-cell precursor ALL patients at first relapse, and 21 paired diagnostic samples were analyzed by multiplex ligation probe-dependent amplification (MLPA). Nineteen paired diagnostic and relapse samples of these 21 patients were also analyzed by SNP arrays. A trend to acquire homozygous CDKN2A/B deletions and a significant increase in the number of copy number alterations (CNA) was observed from diagnosis to first relapse. Evolution from an ancestral clone was the main pattern of clonal evolution. Relapse samples were extremely heterogeneous regarding CNA frequencies. However, CDKN2A/B, PAX5, ETV6, ATM, IKZF1, VPREB1, and TP53 deletions and duplications of 1q, 8q, 17q, 21, X/Y PAR1, and Xp were frequently detected at relapse. Duplications of genes involved in cell proliferation, drug resistance and stem cell homeostasis regulation, as well as deletions of KDM6A and STAG2 genes emerged as specific alterations at relapse. Genomics of relapsed adult B-cell precursor ALL is highly heterogeneous, although some recurrent lesions involved in essential pathways deregulation were frequently observed. Selective and simultaneous targeting of these deregulated pathways may improve the results of current salvage therapies.

FcγRIIb expression in early stage chronic lymphocytic leukemia

In normal B-cells, B-cell antigen receptor (BCR) signaling can be negatively regulated by the low-affinity receptor FcγRIIb (CD32b). To better understand the role of FcγRIIb in chronic lymphocytic leukemia (CLL), we correlated its expression on 155 samples from newly-diagnosed Binet A patients with clinical characteristics and outcome. FcγRIIb expression was similar in normal B-cells and leukemic cells, this being heterogenous among patients and within CLL clones. FcγRIIb expression did not correlate with well known prognostic markers [disease stage, serum beta-2 microglobulin (B2M), IGHV mutational status, expression of ZAP-70 and CD38, and cytogenetics] except for a weak concordance with CD49d. Moreover, patients with low FcγRIIb expression (69/155, 44.5%) required therapy earlier than those with high FcγRIIb expression (86/155, 55.5%) (median 151.4 months vs. not reached; p=.071). These results encourage further investigation on the role of FcγRIIb in CLL biology and prognostic significance in larger series of patients.

Treatment with G-CSF reduces acute myeloid leukemia blast viability in the presence of bone marrow stroma

BACKGROUND

The resulting clinical impact of the combined use of G-CSF with chemotherapy as a chemosensitizing strategy for treatment of acute myeloid leukemia (AML) patients is still controversial. In this study, the effect of ex vivo treatment with G-CSF on AML primary blasts was studied.

METHODS

Peripheral blood mononuclear cells from AML patients were treated with G-CSF at increasing doses, alone or in co-culture with HS-5 stromal cells. Cell viability and surface phenotype was determined by flow cytometry 72 h after treatment. For clonogenicity assays, AML primary samples were treated for 18 h with G-CSF at increasing concentrations and cultured in methyl-cellulose for 14 days. Colonies were counted based on cellularity and morphology criteria.

RESULTS

The presence of G-CSF reduced the overall viability of AML cells co-cultured with bone marrow stroma; whereas, in absence of stroma, a negligible effect was observed. Moreover, clonogenic capacity of AML cells was significantly reduced upon treatment with G-CSF. Interestingly, reduction in the AML clonogenic capacity correlated with the sensitivity to chemotherapy observed in vivo.

CONCLUSIONS

These ex vivo results would provide a biological basis to data available from studies showing a clinical benefit with the use of G-CSF as a priming agent in patients with a chemosensitive AML and would support implementation of further studies exploring new strategies of chemotherapy priming in AML.

The expression level of BAALC-associated microRNA miR-3151 is an independent prognostic factor in younger patients with cytogenetic intermediate-risk acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease whose prognosis is mainly related to the biological risk conferred by cytogenetics and molecular profiling. In elderly patients (⩾60 years) with normal karyotype AML miR-3151 have been identified as a prognostic factor. However, miR-3151 prognostic value has not been examined in younger AML patients. In the present work, we have studied miR-3151 alone and in combination with BAALC, its host gene, in a cohort of 181 younger intermediate-risk AML (IR-AML) patients. Patients with higher expression of miR-3151 had shorter overall survival (P=0.0025), shorter leukemia-free survival (P=0.026) and higher cumulative incidence of relapse (P=0.082). Moreover, in the multivariate analysis miR-3151 emerged as independent prognostic marker in both the overall series and within the unfavorable molecular prognostic category. Interestingly, the combined determination of both miR-3151 and BAALC improved this prognostic stratification, with patients with low levels of both parameters showing a better outcome compared with those patients harboring increased levels of one or both markers (P=0.003). In addition, we studied the microRNA expression profile associated with miR-3151 identifying a six-microRNA signature. In conclusion, the analysis of miR-3151 and BAALC expression may well contribute to an improved prognostic stratification of younger patients with IR-AML.

Prognostic significance of copy number alterations in adolescent and adult patients with precursor B acute lymphoblastic leukemia enrolled in PETHEMA protocols

BACKGROUND

Some copy number alterations (CNAs) have independent prognostic significance for adults with acute lymphoblastic leukemia (ALL).

METHODS

This study analyzed via multiplex ligation-dependent probe amplification the frequency and prognostic impact of CNAs of 12 genetic regions in 142 adolescents and adults with de novo precursor B-cell ALL.

RESULTS

The cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletion (59 of 142 or 42%) was the most frequent CNA, and it was followed by Ikaros family zinc finger 1 (IKZF1) losses (49 of 142 or 35%). IKZF1 deletions were more prevalent in Philadelphia chromosome (Ph)-positive ALL and were associated with advanced age and high white blood cell (WBC) counts. The multivariate analysis showed that advanced age and early B-cell factor 1 (EBF1) deletions were associated with chemotherapy resistance in both the whole series (hazard ratios, 0.949 and 0.135, respectively) and the Ph-negative subgroup (hazard ratios, 0.946 and 0.118, respectively). High WBC counts and focal IKZF1 deletions correlated with disease recurrence (hazard ratios, 1.005 and 1.869, respectively), whereas advanced age and CDKN2A/B losses influenced overall survival in both the whole series (hazard ratios, 1.038 and 2.545, respectively) and the Ph-negative subgroup (hazard ratios, 1.044 and 2.105, respectively).

CONCLUSIONS

Deletions of EBF1, IKZF1, and CDKN2A/B have an independent adverse prognosis for adolescents and adults with B-precursor ALL, and this suggests that these CNAs should be included in the initial risk assessment of ALL.

XIAP inhibitors induce differentiation and impair clonogenic capacity of acute myeloid leukemia stem cells

Acute myeloid leukemia (AML) is a neoplasia characterized by the rapid expansion of immature myeloid blasts in the bone marrow, and marked by poor prognosis and frequent relapse. As such, new therapeutic approaches are required for remission induction and prevention of relapse. Due to the higher chemotherapy sensitivity and limited life span of more differentiated AML blasts, differentiation-based therapies are a promising therapeutic approach. Based on public available gene expression profiles, a myeloid-specific differentiation-associated gene expression pattern was defined as the therapeutic target. A XIAP inhibitor (Dequalinium chloride, DQA) was identified in an in silico screening searching for small molecules that induce similar gene expression regulation. Treatment with DQA, similarly to Embelin (another XIAP inhibitor), induced cytotoxicity and differentiation in AML. XIAP inhibition differentially impaired cell viability of the most primitive AML blasts and reduced clonogenic capacity of AML cells, sparing healthy mature blood and hematopoietic stem cells. Taken together, these results suggest that XIAP constitutes a potential target for AML treatment and support the evaluation of XIAP inhibitors in clinical trials.

Refining the diagnosis and prognostic categorization of acute myeloid leukemia patients with an integrated use of cytogenetic and molecular studies

Significant progress in the understanding of the genetic basis of acute myeloid leukemia (AML) has been made during the last 30 years. The aim of the present study was to assess whether the detection of recurrent gene rearrangements by fluorescent in situ hybridization (FISH) studies and NPM1 and FLT3 gene mutations by molecular studies added clinically relevant information to the karyotype in 113 AML patients. Thus, FISH and molecular studies were found to add new information in 22 and 55% of the patients, respectively, particularly in cases with normal karyotype (NK) or when a cytogenetic analysis failed. Patients with NK changed their genetic risk group to favorable in 27 and 29% of cases using FISH and molecular biology studies, respectively. Our results demonstrate that molecular biology and FISH studies provide relevant information in AML and should be routinely performed.

Acquired mutations in ASXL1 in acute myeloid leukemia: prevalence and prognostic value

Somatic mutations in the additional sex comb-like 1 (ASXL1) gene have been described in various types of myeloid malignancies, including acute myeloid leukemia. Analysis of novel markers, such as ASXL1 mutations, in independent clinical trials is indispensable before considering them for clinical decision-making. We analyzed 882 well-characterized acute myeloid leukemia cases to determine the prevalence and prognostic impact of ASXL1 exon12 mutations. Truncating ASXL1 mutations were present in 46 cases (5.3%). ASXL1 mutations were inversely associated with FLT3 internal tandem duplications and mutually exclusive with NPM1 mutations. ASXL1 mutations were an unfavorable prognostic factor as regards survival (median overall survival 15.9 months vs. 22.3 months; P=0.019), with a significantly lower complete response rate (61% vs. 79.6%; P=0.004). In multivariate analyses, ASXL1 mutations were independently associated with inferior poor overall survival (HR 1.52, P=0.032). In conclusion, ASXL1 mutations are common mutations in acute myeloid leukemia and indicate a poor therapy outcome.