[Molecular and therapeutic advances in Hairy cell leukemia]

Hairy cell leukemia is a rare chronic lymphoproliferative disorder. Its diagnosis remains difficult due to different variant forms and differential diagnosis that are splenic marginal zone lymphoma and b-prolymphocytic leukemia. The prognosis of this malignancy has been transformed by purine nucleoside analogs, interferon, monoclonal antibodies and recombinant immunotoxins usually used in refractory or relapsed disease. The discovery of BRAF V600E mutation has become the milestone in the disease's history since it was uniformly identified in a HCL series in 2011. This mutation, commonly identified in melanoma, involves the protooncogene BRAF, a MAP3Kinase belonging to the RAF-MEK-ERK signaling pathway, which is the central key in several oncogenic processes. This mutation suggests disease-specific oncogene dependence. The detection of this mutation provides an additional diagnosis marker (because not found in variant forms), a best for monitoring minimal residual disease and a therapeutic target with the BRAF inhibitors in specific subgroups of patients, already tested in melanoma. This review aims to summarize the clinical and biological aspects and treatment of hairy cell leukemia and discusses the perspectives provided by the discovery of BRAF mutation in this disease.