High prevalence of MAP2K1 mutations in variant and IGHV4-34–expressing hairy-cell leukemias

Abstract

Paul Meltzer and colleagues report the results of an exome sequencing study of variant and IGHV4-34–expressing hairy-cell leukemias. They identify a high frequency of activating MAP2K1 mutations in these malignancies, suggesting potential therapeutic strategies. To understand the genetic mechanisms driving variant and IGHV4-34–expressing hairy-cell leukemias, we performed whole-exome sequencing of leukemia samples from ten affected individuals, including six with matched normal samples. We identified activating mutations in the MAP2K1 gene (encoding MEK1) in 5 of these 10 samples and in 10 of 21 samples in a validation set (overall frequency of 15/31), suggesting potential new strategies for treating individuals with these diseases.