Activating mutations of receptor tyrosine kinases (RTKs) and their downstream affectors are common in acute myeloid leukemia (AML). We performed mutational analysis of FLT3, c-kit, c-fms, vascular endothelial growth factor (VEGF) receptors (Flt-1, KDR [kinase domain receptor]), and ras genes in a group of 91 pediatric patients with AML treated on Children's Cancer Group clinical trial CCG-2891. Forty-six percent of patients had activating mutations of FLT3 (24.5%), c-kit (3%), or ras (21%) genes. Mutation-positive patients had a higher median diagnostic white blood cell (WBC) count (71.5 vs 19.6 × 109/L; P = .005) and lower complete remission rate (55% versus 76%; P= .046) than mutation-negative patients. The Kaplan-Meier estimate of overall survival (OS) for patients with and without an activating mutation was 34% versus 57%, respectively (P = .035). However, within this group, patients with FLT3/ALM (activation loop mutation) had good outcomes (OS, 86%). Exclusion of the FLT3/ALM from analysis decreased the OS for the remaining mutation-positive patients to 26% (P = .003). Ten of the 23 mutation-positive and 11 of the 34 mutation-negative patients received an allogeneic bone marrow transplant (BMT) in first complete remission (CR). In the mutation-positive group, the disease-free survival (DFS) for the allogeneic BMT recipients was 72% versus 23% for the 13 patients who received chemotherapy or autologous BMT (P = .01). DFS for the mutation-free patients with and without allogeneic BM transplantation was 55% and 40%, respectively (P = .38). Activating mutations in the RTK/ras signaling pathway are common in pediatric AML, and their presence may identify a population at higher risk of poor outcome who may benefit from allogeneic BM transplantation.
ASJC Scopus subject areas
- Cell Biology