Evidence for the important role of the BCR in CLL pathogenesis is given by the fact that the mutational status observed in the BCR sequences is one of the strongest predictors of disease outcome.5, 6 In addition, it constitutes a foundational event in CLL ethiopathogenesis, as suggested by the fact that 20% of CLL cases from unrelated patients display extremely similar, sometimes even identical antigen receptors. Here, BCR is linked to B-cell chronic lymphocytic leukemia.