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Resources for Hematology Fellows

Image Challenge: 54-Year-Old Man With Abnormal Circulating Lymphocytes

Image courtesy of Peter Maslak, MD

What gene is mutated in nearly 100 percent of cases of this disease?

  1. Bcl2 
  2. SF3B1 
  3. BRAF 
  4. p53 


  1. BRAF


In a recent study, the BRAF V600E mutation was identified in 100 percent of patients with hairy cell leukemia, and not in other lymphoproliferative disorders.1Case reports have documented the activity of BRAF inhibitors in relapsed/refractory hairy cell leukemia patients harboring BRAF V600E,2,3  and therefore clinical trials are currently underway to investigate agents such as vemurafenib in this population. 


  1. Arcaini L, Zibellini S, Boveri E, et al. The BRAF V600E mutation in hairy cell leukemia and other mature B-cell neoplasms. Blood. 2012;119:188-191. 
  2. Follows GA, Sims H, Bloxham DM, et al. Rapid response of biallelic BRAF V600E mutated hairy cell leukaemia to low dose vemurafenib. Br J Haematol. 2013;161:150-153. 
  3. Dietrich S, Glimm H, Andrulis M, et al. BRAF inhibition in refractory hairy-cell leukemia. N Engl J Med. 2012;366:2038-2040. 

Image challenge courtesy of Matthew Ulrickson, MD, University of Washington, Chair, Trainee Council