Real‐time PCR‐based analysis of BRAF V600E mutation in low and intermediate grade lymphomas confirms frequent occurrence in hairy cell leukaemia

Hairy cell leukaemia (HCL) is a rare type of B‐cell non‐Hodgkin lymphoma (B‐NHL), which is not known to be associated with any characteristic recurrent karyotypic abnormality. A recent study that used massively parallel whole exome sequencing identified an activating V600E mutation in BRAF, which appeared specific for HCL. Here, we confirm the specificity of BRAF V600E for HCL among low and intermediate grade B‐NHL and describe a real‐time polymerase chain reaction method for detecting this mutation in cases with low tumour burden. The V600E mutation does not appear to be associated with microsatellite instability, unlike the case in colorectal cancer. Thus, in conjunction with prior data, our results suggest incorporation of BRAF V600E mutation analysis in the diagnostic workup of HCL cases. Additionally, targeting the Ras‐Raf‐Mek‐Erk‐Map kinase pathway should be investigated as a potential therapeutic strategy for patients with this disease. Copyright © 2011 John Wiley & Sons, Ltd.