PROGNOSTIC SIGNIFICANCE OF NRAS GENE MUTATIONS IN CHILDREN WITH ACUTE MYELOGENOUS LEUKEMIA

NRAS mutations are the most commonly detected molecular abnormalities in hematologic malignancies, especially in those of myeloid origin.We aimed to determine the frequency of NRAS (NRAS(mutant)) mutation; and its prognostic significance in Egyptian children with acute myelogenous leukemia (AML).Peripheral blood and bone marrow (BM) samples were taken from 39 de novo pediatric AML patients. Twenty subjects with matched age and sex were selected as a control group. Samples from patients and control were analyzed for Exons 1, 2 of NRAS gene using genomic PCR-SSCP method.NRAS mutations at the time of diagnosis was found in 6/39 (15.4%) AML cases. Patients with NRAS(mutant) had no significant improved clinical outcome than patients without mutation. Patients with NRAS(mutant) had similar complete remission (CR) rates compared with non-mutated patients (66.7% vs. 69.5%, P=0.43). Those in CR had a similar relapse rate regardless of the presence of NRAS(mutant) (RR 33.4% vs. 30.2%, P=0.26). However, an adverse prognosis for 3 year overall survival (OS) was associated with the presence of NRAS mutations. This adverse prognosis associated with NRAS mutations was also observed in terms of disease-free survival (DFS) (P=0.007). Univariate analysis showed that unfavorable prognostic factors for DFS were cytogenetic data (P = 0.005) and the NRAS gene mutation (P = 0.002).NRAS(mutant) did not contribute to increase the disease recurrence, however NRAS(mutant) was found to be a poor prognostic factor for children with AML. Further studies to confirm these findings are required because of the small number of patients with NRAS mutation.