Prevalence of gene mutation and its expression in Brazilian pediatric B-ALL patients: clinical implications.

INTRODUCTION

There is consistent evidence that may be a driver gene in B-ALL and that selected cases may benefit from the use of FLT3 inhibitors. Our study was conducted to evaluate the frequency and types of FLT3 mutations in pediatric patients with B-ALL, the relative expression of this gene, and their influence on clinical evolution.

METHODS

We evaluated 156 children with B-ALL treated between July 2018 and September 2023. Screening for FLT3 mutations was performed using RFLP and fragment analysis, while FLT3 expression was assessed by qPCR.

RESULTS

-TKD and/or -JM-INDEL mutations were found in 8 patients (5.1%). We did not identify any ITD-type mutations. None of the patients with identified mutations presented recurrent rearrangements in B-ALL or alterations in the , , or genes, suggesting that mutation may serve as the driving mechanism for leukemia in these cases. Two (2/8) patients with mutations experienced disease relapse. Although we did not observe overexpression among patients with mutations, expression levels were higher in these patients compared to WT patients. Four -WT patients presented overexpression, defined as RQ > 10. mutations or overexpression were not associated with relapses or survival rates.

DISCUSSION

Our findings do not support the inclusion of as a routine marker in the risk stratification of B-ALL patients; nevertheless, FLT3 alterations may be relevant for guiding personalized treatment approaches in specific clinical contexts.