First suggested in an anecdotal case,73 the clinical efficacy of the BRAF inhibitor vemurafenib was recently evaluated by two single-arm phase II multicenter trials, in Italy and the United States, in 25 and 24 patients with relapsed or refractory HCL, respectively.22 Vemurafenib, given at its standard dose of 960 mg twice daily for a median of 16 or 18 weeks, produced response rates of 96% and 100% in the two studies, of which 35% and 42% were CRs (Fig 1, middle right), respectively. This evidence concerns the gene BRAF and hairy cell leukemia.