Acute Myeloid Leukemia Case Harboring Unusual FLT3 Variant: Somatic vs Germline?

Abstract

FLT3 mutations are considered a prognostic and predictive marker. Here we report on a patient with a rare FLT3 germline variant in the context of relapsed acute myeloid leukemia (AML). A female patient aged 57 years presented with AML with mutations in the IDH2, ASXL1, and DNMT3A genes. She underwent allogenic hematopoietic stem cell transplant but relapsed 2 years posttransplant. Targeted next generation sequencing identified a new missense variant in the FLT3 tyrosine kinase domain c.2440G > T (p.A814S). The treating team considered the possibility of patient eligibility for an FLT3 inhibitor. Because both somatic and germline mutations can be identified in tumor tissue with high-throughput sequencing, it becomes important to distinguish the origin of these alterations when possible-especially, in this challenging case, to define the treatment modality. Simultaneous tumor/germline sequencing allows for the identification of rare germline mutations and may help in determining their significance in the pathogenesis of disease.

Keywords: FLT3; Cytogenetically normal (CN)-AML; Hematopathology; Highthroughput sequencing; Molecular pathology; Somatic vs Germline alterations/mutations.