RAS mutations are frequent in FAB type M4 and M5 of acute myeloid leukemia, and related to late relapse: a study of the Japanese Childhood AML Cooperative Study Group

Mutations in are frequent in acute myeloid leukemia (AML), and are thought to contribute to leukemogenesis in a subset of patients; however, their prognostic significance has not been firmly established. One hundred and fifty-seven pediatric patients with AML were analyzed for and mutations around hot spots at codons 12, 13, and 61. Twenty-nine patients (18.5%) had an activating mutation of . We found mutations to be more frequent than mutations (18/29, 62.1% of patients with mutation), in contrast to previous reports (18-40%). The frequency of mutation was higher in French-American-British types M4 and M5 than other types ( = 0.02). There were no significant differences in other clinical manifestations or distribution in cytogenetic subgroups, or aberrations of other genes, including mutation, -ITD, and -PTD, between patients with and without mutations. No significant differences were observed in the 3-year overall survival and disease-free survival; however, the presence of mutation was related to late relapse. The occurrence of clinical events at relatively late period should be monitored for in AML patients with mutations in .