Immunophenotypic and molecular features of ‘cuplike’ acute myeloid leukemias

Nuclear invaginations, also referred to as fishmouth or cuplike nuclei, have long been identified in microgranular APL, myelomonocytic and monocytic AMLs. More recently, this typical morphological feature has been associated with NPM1 and FLT3 mutations, as well as with the lack of CD34 and HLA‐DR expression. In this study, we retrospectively analyzed the morphologic, immunophenotypic, cytogenetic, and molecular features of 68 patients with AML. A cuplike nuclear invagination was detected in more than 10% of blast cells in 15 (22%) cases. Our data show that a cuplike morphology is associated with FLT3‐ITD positivity, as well as with the loss of CD34 and HLA‐DR expression. The results were not significantly modified when a higher cutoff of cuplike cells was used. Our results are not sufficient to suggest that cuplike AML could represent a distinct subtype, but further investigations could yield a better characterization of this feature in patients with AML.     

IDH1 and IDH2 mutations confer an adverse effect in patients with acute myeloid leukemia lacking the NPM1 mutation

We examined the incidence and prognostic effect of IDH1 and IDH2 mutations in 233 Japanese adults with acute myeloid leukemia (AML). IDH1 R132 mutations were detected in 20 (8.6%) patients with AML. IDH2 mutations were found in 19 (8.2%, 17 R140 and two R172) patients. IDH1 and IDH2 mutations were mutually exclusive and were associated with normal karyotype AML, cytogenetic intermediate‐risk group, and NPM1 mutations. Five‐year overall survival (OS) rates were significantly lower (15.6%) in patients harboring the IDH mutations than in patients lacking the IDH mutation (32.0%) in the entire cohort of AML (P = 0.005). Among patients aged 59 yr or younger with IDH mutations, 5‐yr OS in patients who underwent allogeneic stem cell transplantation (SCT) was significantly higher than that in those not receiving allogeneic SCT (50% vs. 10.6%, P = 0.020). Of 51 patients with NPM1 mutations, there was no significant difference in 5‐yr OS rates between patients with and those without the IDH mutations. In contrast, among 175 patients lacking the NPM1 mutations, 5‐yr OS rate in patients with IDH mutations was significantly lower than that in those without IDH mutations (0% vs. 34.7%, P = <0.001). These data suggest that IDH mutations have an unfavorable effect in AML, especially AML with the NPM1 wild type and younger AML patients with IDH mutations may benefit from allogeneic SCT.     

Gene mutation patterns and their prognostic impact in a cohort of 1185 patients with acute myeloid leukemia

To evaluate the prognostic value of genetic mutations for acute myeloid leukemia (AML) patients, we examined the gene status for both fusion products such as AML1 (CBFα)-ETO, CBFβ-MYH11, PML-RARα, and MLL rearrangement as a result of chromosomal translocations and mutations in genes including FLT3, C-KIT, N-RAS, NPM1, CEBPA, WT1, ASXL1, DNMT3A, MLL, IDH1, IDH2, and TET2 in 1185 AML patients. Clinical analysis was mainly carried out among 605 cases without recognizable karyotype abnormalities except for 11q23. Of these 605 patients, 452 (74.7%) were found to have at least 1 mutation, and the relationship of gene mutations with clinical outcome was investigated. We revealed a correlation pattern among NPM1, DNMT3A, FLT3, IDH1, IDH2, CEBPA, and TET2 mutations. Multivariate analysis identified DNMT3A and MLL mutations as independent factors predicting inferior overall survival (OS) and event-free survival (EFS), whereas biallelic CEBPA mutations or NPM1 mutations without DNMT3A mutations conferred a better OS and EFS in both the whole group and among younger patients < 60 years of age. The use of molecular markers allowed us to subdivide the series of 605 patients into distinct prognostic groups with potential clinical relevance.     

Gene mutation and AML pathogenesis

In their large study of 1185 patients with acute myeloid leukemia (AML), Shen and colleagues have dissected the overlapping incidences and prognostic significances of mutations of the 12 genes most frequently mutated in AML,including FLT3, NPM1, CEBPA, KIT, N-RAS, MLL, WT1, IDH1/2, TET2, DNMT3A, and ASXL1.     

Characteristics,clinical outcome,and prognostic significance of IDH mutations in AML

The pathophysiology of IDH mutations in tumorigenesis is increasingly described, yet the prognostic significance of IDH1 and IDH2 mutations in AML remains controversial. The primary objective of this study was to define the natural history and prognosis of patients with AML and IDH1 or IDH2 mutations and provide historical survival expectations. A total of 826 patients treated from 2010 to 2014 at a single institution were evaluated, including 167 patients (20%) with AML and IDH1 or IDH2 mutations. Median age was 62 years (range 18–92). There were 59 IDH1‐R132, 83 IDH2‐R140, and 23 IDH2‐R172 mutations. Clinicopathologic characteristics associated with IDH‐mutations included older age, less frequent therapy‐related status, and increased incidence of intermediate‐risk cytogenetics, FLT3‐ITD mutations, and NPM1 mutations. Remission rates (CR/CRi) by AML treatment status were: induction, 68%; Salvage‐1 (S1), 42%; and Salvage‐2 and beyond (S2+), 27%. No difference in response was identified by IDH mutation status. Similarly, overall survival (OS) was not dependent on IDH status within any cohort. The median OS was 15.4 months in induction, 8.7 months in S1, and 4.8 months in S2+. This analysis defines the clinical outcome associated with IDH‐mutations in both the front‐line and salvage AML treatment settings, and confirms that response rate and OS for both IDH‐mutated and IDH wild‐type AML patients is comparable. This provides contemporary data to be used for comparison with results of novel investigational (e.g., selective IDH inhibitor) strategies. Am. J. Hematol. 90:732–736, 2015. © 2015 Wiley Periodicals, Inc.     

The combination of NPM1, DNMT3A,and IDH1/2 mutations leads to inferior overall survival in AML

Acute myeloid leukemia (AML) is a genetically heterogeneous disease with a clinical course predicted by recurrent cytogenetic abnormalities and/or gene mutations. The NPM1 insertion mutations define the largest distinct genetic subset, ∼30% of AML, and is considered a favorable risk marker if there is no (or low allelic ratio) FLT3 internal tandem duplication (FLT3 ITD) mutation. However, ∼40% of patients with mutated NPM1 without FLT3 ITD still relapse, and the factors that drive relapse are still not fully understood. We used a next-generation sequencing panel to examine mutations at diagnosis; clearance of mutations after therapy, and gain/loss of mutations at relapse to prioritize mutations that contribute to relapse. Triple mutation of NPM1, DNMT3A and IDH1/2 showed a trend towards inferior overall survival in our discovery dataset, and was significantly associated with reduced OS in a large independent validation cohort. Analysis of relative variant allele frequencies suggests that early mutation and expansion of DNMT3A and IDH1/2 prior to acquisition of NPM1 mutation leads to increased risk of relapse. This subset of patients may benefit from allogeneic stem cell transplant or clinical trials with IDH inhibitors.     

Acute myeloid leukemia with myelodysplasia-related changes are characterized by a specific molecular pattern with high frequency of ASXL1 mutations

To determine whether the distinct and heterogeneous WHO category called "AML with myelodysplasia-related changes" (MRC-AML), presents specific molecular alterations we searched for mutations in genes known to be mutated in malignant myeloid diseases. In 48 MRC-AML patients analyzed, we found 17 mutations in ASXL1 (35%), eight in RUNX1 (17%), seven in TET2 (15%), 12 in IDH (n = 2) or IDH2 (n = 10) (25%), four in DNMT3A (8%), four in NPM1 (8%), and one in FLT3 (2%). Mutations were more frequent in the intermediate cytogenetic (IC) subgroup of 36 patients than in the unfavorable karyotype subgroup, with an average ratio mutations/patients of 1.36 [0-3] vs. 0.33 [0-2] (P < 0.001). Then, we compared these 36 patients with IC MRC-AML with a control panel of 37 no-MRC-AML patients, who had both IC and no dysplasia. IC MRC-AMLs were associated with higher incidence of ASXL1 mutations (47% vs. 0%, P < 0.001) and lower incidence of DNMT3A (6% vs. 38%, P = 0.001), NPM1 (11% vs. 62%, P < 0.001) and FLT3 (3% vs. 49%, P < 0.001) mutations. No difference was found in the incidence of IDH1/2 or TET2 mutations according to the presence of dysplasia. Complete remission rate after intensive treatment was lower in the MRC-AML group than in the no-MRC-AML group (48% vs. 78%, P = 0.023) and in wild type NPM1 patients (50% vs. 84%, P = 0.009). Our study showed that MRC-AML as defined in the WHO 2008 classification presents a specific mutation pattern characterized by a high frequency of ASXL1 mutations and a low rate of NPM1, FLT3, and DNMT3A mutations.     

FLT3 and NPM1 mutations in a cohort of AML patients and detection of a novel mutation in tyrosine kinase domain of FLT3 gene from Western India

Acute myeloid leukemia (AML) is an aggressive hematological disorder characterized by the loss of ability of the hematopoietic progenitor cells to differentiate and proliferate normally leading to an accumulation of immature myeloid cells in the bone marrow. Several novel molecular genetic aberrations in FLT3 and NPM1 have been shown to have a prognostic impact in AML, particularly in those having normal karyotype. Though there is substantial amount of data on these mutations from western literature, there is surprisingly little data from Indian subcontinent on the frequency of this mutation in AML patients from India. The present study screens a large cohort of non-acute promyelocytic leukemia (APL) AML patients (207 patients) for the presence of FLT3 and NPM1 mutations and further correlates with cytogenetics, immunophenotypic characteristics and with follow-up data wherever available. During the course of study, 56 APL patients were also studied. Briefly, both FLT3 (internal tandem duplication (ITD) in 19.4?% and tyrosine kinase domain (TKD) in 9?%) and NPM1 mutations were detected in 28.4?% of the total non-APL AML patients screened showing distinct correlations with hematologic, immunophenotypic, cytogenetics characteristics and follow-up. With regards to adult APL patients, 22.2 and 32.6?% of the patients showed FLT3 and NPM1 mutation, respectively. In the pediatrics age group (<15?years), 23 and16?% of patients with APL showed FLT3 and NPM1 mutation, respectively, while in non-APL patient is this age group, 23?% of patients showed both FLT3 and NPM1 mutation. NPM1 mutation was distinctly uncommon in younger age group of patients. In contrast to report elsewhere, most of our FLT3 mutation was in exon 11 rather than in exon 12. FLT3mutation due to ITD or TKD mutation was detected in 2:1 ratio in our patients and a new TKD mutation was also detected S840G in an M5 patient who did not go into remission and had a short survival of 3?months from diagnosis. Generally, patients with NPM1 mutation had a very high white cell count but they went into remission more often than those with wild (Wt)-type allele (written as NPM1? and FLT3?, respectively) and FLT3 mutation. These patients also tended to have significantly lower expression of CD34 antigen on flowcytometry. Distinct prognostic subclasses of adult AML patients were identified based on the presence of NPM1 and FLT3 mutations.     

IDH2 mutations are frequent in Chinese patients with acute myeloid leukemia and associated with NPM1 mutations and FAB-M2 subtype

Introduction: Gene mutations play an important role in acute myeloid leukemia (AML) pathogenesis. Several genes have been identified in AML, such as FLT3, KIT, NPM1, and JAK2. This study investigated the frequency of novel mutations in IDH1 (amino acid R132) and IDH2 (R140 and R172) and analyzed their impact on disease biology and interaction with other mutations in Chinese patients with de novo AML. Methods: A total of 195 patients were screened for mutations in the IDH1, IDH2, JAK2 V617F, NPM1, FLT3, and KIT genes, using polymerase chain reaction (PCR)-based and direct sequencing assays. Results: IDH mutations occurred at a considerable frequency of 15.89% in Chinese AML cases; IDH2 R140Q was the most frequent genetic alteration and was associated with older age, normal karyotype, and French-American-British classification M2 at diagnosis. There was a strong association of IDH2 mutation with NPM1 mutations and a trend with FLT3-internal-tandem duplication. Conclusion: IDH mutations may be a novel genetic marker in cytogenetically normal AML and may cooperate in leukemogenesis.     

TET2 mutation is an unfavorable prognostic factor in acute myeloid leukemia patients with intermediate-risk cytogenetics

The studies concerning clinical implications of TET2 mutation in patients with primary acute myeloid leukemia (AML) are scarce. We analyzed TET2 mutation in 486 adult patients with primary AML. TET2 mutation occurred in 13.2% of our patients and was closely associated with older age, higher white blood cell and blast counts, lower platelet numbers, normal karyotype, intermediate-risk cytogenetics, isolated trisomy 8, NPM1 mutation, and ASXL1 mutation but mutually exclusive with IDH mutation. TET2 mutation is an unfavorable prognostic factor in patients with intermediate-risk cytogenetics, and its negative impact was further enhanced when the mutation was combined with FLT3-ITD, NPM1-wild, or unfavorable genotypes (other than NPM1(+)/FLT3-ITD(-) or CEBPA(+)). A scoring system integrating TET2 mutation with FLT3-ITD, NPM1, and CEBPA mutations could well separate AML patients with intermediate-risk cytogenetics into 4 groups with different prognoses (P < .0001). Sequential analysis revealed that TET2 mutation detected at diagnosis was frequently lost at relapse; rarely, the mutation was acquired at relapse in those without TET2 mutation at diagnosis. In conclusion, TET2 mutation is associated with poor prognosis in AML patients with intermediate-risk cytogenetics, especially when it is combined with other adverse molecular markers. TET2 mutation appeared to be unstable during disease evolution.     

Acute myeloid leukaemia genomics

Acute myeloid leukaemia (AML) is a biologically complex, molecularly and clinically heterogeneous disease. Despite major advances in understanding the genetic landscape of AML and its impact on the pathophysiology and biology of the disease, standard treatment options have not significantly changed during the past three decades. AML is characterized by multiple somatically acquired mutations that affect genes of different functional categories. Mutations in genes encoding epigenetic modifiers, such as DNMT3A, ASXL1, TET2, IDH1, and IDH2, are commonly acquired early and are present in the founding clone. By contrast, mutations involving NPM1 or signalling molecules (e.g., FLT3, RAS gene family) are typically secondary events that occur later during leukaemogenesis. This review aims to provide an overview of advances in new prognostic markers, including targetable mutations that will probably guide the development and use of novel molecularly targeted therapies.     

TET2, ASXL1, IDH1, IDH2, and c-CBL genes in JAK2- and MPL-negative myeloproliferative neoplasms

Mutations in the TET2 and ASXL1 genes have been described in approximately 14% and 8% of patients, respectively, with classic myeloproliferative neoplasms (MPN), but their role as possible new diagnostic molecular markers is still inconclusive. In addition, other genes such as IDH1, IDH2, and c-CBL have also been reported in several myeloid neoplasms. We have studied the mutational status of TET2 (complete coding region), ASXL1 (exon12), IDH1 (R132), IDH2 (R140 and R172), and c-CBL (exons 8 and 9) in 62 MPN patients (52 essential thrombocythemia (ET), five polycythemia vera (PV), and five primary myelofibrosis (PMF)) negative for both JAK2 (V617F and exon 12) and MPL (exon 10) mutations. Pathogenic alterations in the TET2 gene were detected in three out 52 ET cases (4.8%). ASXL1 gene pathogenic mutations were also detected in three cases (two ET and one PMF). One ET patient harbored, simultaneously, one TET2 and one ASXL1 mutations. Mutations in the TET2 and ASXL1 genes showed no association with the JAK2 46/1 haplotype. Analysis of a JAK2V617F-positive cohort of 50 ET patients showed no mutations in either the TET2 or ASXL1 genes. Regarding IDH1, IDH2, and c-CBL genes, no mutations were found in any patient. In conclusion, TET2 and ASXL1 pathogenic mutations are found in 8% of MPN lacking JAK2 and MPL mutations, whereas IDH1, IDH2, and c-CBL mutations are not detected in this subset of patients.     

Comparison of high‐resolution melting analysis with direct sequencing for the detection of recurrent mutations in DNA methyltransferase 3A and isocitrate dehydrogenase 1 and 2 genes in acute myeloid leukemia patients

Acute myeloid leukemia (AML) cells harbor frequent mutations in genes responsible for epigenetic modifications. Increasing evidence of clinical role of DNMT3A and IDH1/2 mutations highlights the need for a robust and inexpensive test to identify these mutations in routine diagnostic work‐up. Herein, we compared routinely used direct sequencing method with high‐resolution melting (HRM) assay for screening DNMT3A and IDH1/2 mutations in patients with AML. We show very high concordance between HRM and Sanger sequencing (100% samples for IDH2‐R140 and DNMT3‐R882 mutations, 99% samples for IDH1‐R132 and IDH2‐R172 mutations). HRM method reported no false‐negative results, suggesting that it can be used for mutations screening. Moreover, HRM displayed much higher sensitivity in comparison with DNA sequencing in all assessed loci. With Sanger sequencing, robust calls were observed when the sample contained 50% of mutant DNA in the background of wild‐type DNA. In marked contrast, the detection limit of HRM improved down to 10% of mutated DNA. Given the ubiquitous presence of wild‐type DNA background in bone marrow aspirates and clonal variations regarding mutant allele burden, these results favor HRM as a sensitive, specific, labor‐, and cost‐effective tool for screening and detection of mutations in IDH1/2 and DNMT3A genes in patients with AML.     

Clonal leukemic evolution in myelodysplastic syndromes with TET2 and IDH1/2 mutations

Somatic mutations of TET2, IDH1, and IDH2 have been described in myelodysplastic syndrome. The impact of these mutations on outcome of myelodysplastic syndrome and their progression to secondary acute myeloid leukemia remains unclear. Mutation status of TET2, IDH1 and IDH2 was investigated in a cohort of 46 paired myelodysplastic syndrome/acute myeloid leukemia samples and 122 non-paired cases with de novo myelodysplastic syndrome, to clarify their roles in the evolution of myelodysplastic syndrome to acute myeloid leukemia. Among the 168 de novo myelodysplastic syndrome patients, the frequency of TET2, IDH1, and IDH2 mutations was 18.5%, 4.2% and 6.0%, respectively. TET2/IDH mutations had no impact on survivals, while TET2 mutations were significantly associated with rapid progression to acute myeloid leukemia. Seventeen of the 46 paired myelodysplastic syndrome/secondary acute myeloid leukemia samples harbored TET2/IDH mutations; none acquired these mutations in acute myeloid leukemia phase. Progression to acute myeloid leukemia was accompanied by evolution of a novel clone or expansion of a minor pre-existing subclone of one or more distinct mutations in 12 of the 17 cases with TET2/IDH mutations. A minor subclone in 3 cases with biallelic TET2 inactivation subsequently expanded, indicating biallelic TET2 mutations play a role in acute myeloid leukemia progression. Twelve patients acquired other genetic lesions, and/or showed increased relative mutant allelic burden of FLT3-ITD, N/K-RAS, CEBPA or RUNX1 during acute myeloid leukemia progression. Our findings provide a novel insight into the role of TET2/IDH mutation in the pathogenesis of myelodysplastic syndrome and subsequent progression to acute myeloid leukemia.     

Identification of relapse-associated gene mutations by next-generation sequencing in low-risk acute myeloid leukaemia patients

Recommended genetic categorization of acute myeloid leukaemias (AML) includes a favourable-risk category, but not all these patients have good prognosis. Here, we used next-generation sequencing to evaluate the mutational profile of 166 low-risk AML patients: 30 core-binding factor (CBF)-AMLs, 33 nucleophosmin (NPM1)-AMLs, 4 biCEBPα-AMLs and 101 acute promyelocytic leukaemias (APLs). Functional categories of mutated genes differed among subgroups. NPM1-AMLs showed frequent variations in DNA-methylation genes (DNMT3A, TET2, IDH1/2) (79%), although without prognostic impact. Within this group, splicing-gene mutations were an independent factor for relapse-free (RFS) and overall survival (OS). In CBF-AML, poor independent factors for RFS and OS were mutations in RAS pathway and cohesin genes, respectively. In APL, the mutational profile differed according to the risk groups. High-risk APLs showed a high mutation rate in cell-signalling genes (P = 0·002), highlighting an increased incidence of FLT3 internal tandem duplication (ITD) (65%, P < 0·0001). Remarkably, in low-risk APLs (n = 28), NRAS mutations were strongly correlated with a shorter five-year RFS (25% vs. 100%, P < 0·0001). Overall, a high number of mutations (≥3) was the worst prognostic factor RFS (HR = 2·6, P = 0·003). These results suggest that gene mutations may identify conventional low-risk AML patients with poor prognosis and might be useful for better risk stratification and treatment decisions.     

Clonal hierarchy of main molecular lesions in acute myeloid leukaemia

Genetic mutations in acute myeloid leukaemia (AML) are assumed to occur in a sequential order; however, the predominant hierarchical roles of specific mutated genes have not been fully described. In this study, we aimed to determine the clonal involvement of the most frequent AML-associated mutations. Using a targeted sequencing panel for 18 genes, we traced changes and relative clonal contribution of mutations in 52 patients. We analysed 35 pairs of diagnosis and relapse samples, 27 pairs of primary samples and corresponding patient-derived xenografts, and 34 pairs of total leukocytes and corresponding isolated primitive cells or blast populations. In both relapse and xenografts, we observed conservation of main leukaemic clones and variability was limited to subclones with late-acquired mutations. AML evolution thus mainly involved modification of subclones while the clonal background remained unchanged. NPM1 mutations were identified as the most probable leukaemia-transformation lesion, remaining conserved in contrast to high variation of accompanying subclonal FLT3 and NRAS mutations. DNMT3A mutations represented the most stable mutations forming a preleukaemic background in most samples. Mutations in genes IDH1/2, TET2, RUNX1, ASXL1 and U2AF1 were detected both as preleukaemic and as subclonal lesions, suggesting a non-specific order of acquisition.     

TET2 mutations,myelodysplastic features,and a distinct immunoprofile characterize blastic plasmacytoid dendritic cell neoplasm in the bone marrow

Distinguishing blastic plasmacytoid dendritic cell neoplasm (BPDCN) from acute myeloid leukemia (AML) is gaining increased importance because of emerging differences in therapeutic approaches, and this distinction can be problematic in bone marrow specimens. We identified retrospectively 16 patients with bone marrow involvement by BPDCN: 11 men and 5 women with a median age of 62.5 years (range, 19–86 years). Myelodysplastic changes were observed in five patients. Immunophenotypic analysis showed that the neoplastic cells were positive for CD4, CD123, TCL‐1, and HLA‐DR and were negative for CD3, CD8, CD13, CD19, CD34, and myeloperoxidase. Other antigens expressed by subsets of BPDCN cases included the following: CD56 (13/15; 81%), CD33 (7/10; 70%), CD7 (11/14; 69%), TdT (5/15; 33%), CD2 (5/11; 31%), CD117 (2/9; 22%), and CD5 (2/13; 15%). Conventional cytogenetic analysis showed chromosomal abnormalities in 6 of 13 (46%) cases analyzed, of which 3 cases had ?13/13q?. Targeted next‐generation sequencing performed on five BPDCN cases identified TET2 (ten eleven translocation 2) mutations and no other AML‐associated mutations. In conclusion, BPDCN in the bone marrow has a characteristic immunoprofile (CD4+, CD56+, CD123+, and TCL‐1+) and appears to be commonly associated with myelodysplastic features and a high frequency of TET2 mutations in the absence of other mutations commonly observed in AML. Am. J. Hematol. 88:1055–1061, 2013. © 2013 Wiley Periodicals, Inc.     

Prognostic Impact of NPM1 Mutations in Serbian Adult Patients with Acute Myeloid Leukemia

Based on current findings, the presence of NPM1 mutations in acute myeloid leukemia (AML) patients is associated with an increased probability of complete remission (CR) and better overall survival (OS). We determined the incidence and prognostic relevance of NPM1 mutations, their association with FLT3 and IDH mutations, and other clinical characteristics in Serbian adult AML patients. Samples from 111 adult de novo AML patients, including 73 AML cases with a normal karyotype (NK-AML), were studied. NPM1, FLT3, and IDH mutations were detected by PCR and direct sequencing. NPM1 mutations were detected in 22.5% of patients. The presence of NPM1 mutations predicted a low CR rate and shorter OS. NPM1 mutations showed an association with both FLT3 and IDH mutations. Survival analysis based on NPM1/FLT3 mutational status revealed a lower OS for NPM1(+)/FLT3(-) compared to the NPM1(-)/FLT3(-) group in NK-AML patients. The lack of impact or unfavorable prognostic effect of NPM1 mutations found in this study can be assigned to a small cohort of analyzed AML patients, as can the presence of FLT3 and IDH mutations or other genetic lesions that cooperate with NPM1 mutations influencing prognosis.     

TET2 gene mutation is unfavorable prognostic factor in cytogenetically normal acute myeloid leukemia patients with NPM1+ and FLT3-ITD− mutations

Cytogenetically normal acute myeloid leukemia (cn-AML) is a group of heterogeneous diseases. Gene mutations are increasingly used to assess the prognosis of cn-AML patients and guide risk-adapted treatment. In the present study, we analyzed the molecular genetics characteristics of 373 adult cn-AML patients and explored the relationship between TET2 gene mutations or different genetic mutation patterns and prognosis. We found that 16.1 % of patients had TET2 mutations, 31.6 % had FLT3 internal tandem duplications (ITDs), 6.2 % had FLT3 tyrosine kinase domain mutations, 2.4 % had c-KIT mutations, 37.8 % had NPM1 mutations, 11.3 % had WT1 mutations, 5.9 % had RUNX1 mutations, 11.5 % had ASXL1 mutations, 3.8 % had MLL-PTDs, 7.8 % had IDH1 mutations, 7.8 % had NRAS mutations, 12.3 % had IDH2 mutations, 1.6 % had EZH2 mutations, and 14.7 % had DNMT3A mutations, while none had CBL mutations. Gene mutations were detected in 76.94 % (287/373) of all patients. In the NPM1m⁺ patients, those with TET2 mutations were associated with a shorter median overall survival (OS) as compared to TET2 wild-type (wt) patients (9.9 vs. 27.0 months, respectively; P = 0.023); Interestingly, the TET2 mutation was identified as an unfavorable prognostic factor and was closely associated with a shorter median OS as compared to TET2-wt (9.5 vs. 32.2 months, respectively; P = 0.013) in the NPM1m⁺/FLT3-ITDm^? patient group. Thus, identification of TET2 combined with classic NPM1 and FLT3-ITD mutations allowed us to stratify cn-AML into distinct subtypes.