Since the initial report of the BRAF V600E mutation in hairy cell leukemia (HCL) [1], this mutation has been sought in numerous cohorts, the majority of which confirm the presence of the BRAF V600E in classical HCL and its absence in HCL variant and other mature B-cell malignancies, therefore, providing a rationale for targeted therapy [2]. This evidence concerns the gene BRAF and hairy cell leukemia.