High Throughput Molecular Characterization of Normal Karyotype Acute Myeloid Leukemia in the Context of the Prospective Trial 02/06 of the Northern Italy Leukemia Group (NILG)

Abstract

By way of a Next-Generation Sequencing NGS high throughput approach, we defined the mutational profile in a cohort of 221 normal karyotype acute myeloid leukemia (NK-AML) enrolled into a prospective randomized clinical trial, designed to evaluate an intensified chemotherapy program for remission induction. NPM1, DNMT3A, and FLT3-ITD were the most frequently mutated genes while DNMT3A, FLT3, IDH1, PTPN11, and RAD21 mutations were more common in the NPM1 mutated patients (p < 0.05). IDH1 R132H mutation was strictly associated with NPM1 mutation and mutually exclusive with RUNX1 and ASXL1. In the whole cohort of NK-AML, no matter the induction chemotherapy used, by multivariate analysis, the achievement of complete remission was negatively affected by the SRSF2 mutation. Alterations of FLT3 (FLT3-ITD) and U2AF1 were associated with a worse overall and disease-free survival (p < 0.05). FLT3-ITD positive patients who proceeded to alloHSCT had a survival probability similar to FLT3-ITD negative patients and the transplant outcome was no different when comparing high and low-AR-FLT3-ITD subgroups in terms of both OS and DFS. In conclusion, a comprehensive molecular profile for NK-AML allows for the identification of genetic lesions associated to different clinical outcomes and the selection of the most appropriate and effective treatment strategies, including stem cell transplantation and targeted therapies.

Keywords: Acute Myeloid Leukemia; NGS; molecular marker.

Figure 1

Kaplan-Meier curves of Overall Survival (OS), according to induction and consolidation treatments, in complete remission patients. 5-year OS estimates are reported. p values assessed comparing groups are: HSCT, sHD vs. ICE: p = 0.48; No HSCT, sHD vs. ICE: p = 0.52; sHD, HSCT vs. no HSCT: p = 0.03; ICE, HSCT vs. no HSCT: p = 0.01.

Figure 2

Frequency of different mutated genes according to induction treatment. CEBPA2 and CEBPA1 indicate the presence of double or single mutation, respectively.

Figure 3

Frequency of different mutated genes in our cohort of patients. In CEBPA line, dark pink indicates the presence of a double mutation.

Figure 4

Pairwise association among gene mutations. The odds ratio of the association is color coded: blue colors indicate a negative association while red colors indicate a positive association. In addition, differential green intensity represent a different co-occurrence of mutations in terms of number of patients. Triangle indicates a group of genes which frequently co-mutate in NPM1 wild-type AML. CEBPA2 and CEBPA1 indicate the presence of double or single mutation, respectively.

Figure 5

Kaplan-Meier curves of Overall Survival (OS), according to FLT3-ITD ratio. (A) All patients; (B) NPM1 positive patients; (C) NPM1 wild-type patients. 5-year OS estimates and p values are reported.

Figure 6

Kaplan-Meier curves of Overall Survival (OS) in different consolidation programs. (A) Patients receiving allogeneic stem cell transplantation, according to FLT3-ITD ratio; (B) Patients receiving other consolidation program, according to FLT3-ITD and NPM1 mutations. 5-year OS estimates and p values are reported.