BCR and B-cell chronic lymphocytic leukemia: Early genetic studies of the immunoglobulin heavy-chain variable region (IGHV), that encodes part of the B-cell receptor (BCR), identified two disease subtypes based on the degree of somatic hypermutation (SH) of the IGHV locus whereby CLL with mutated IGHV genes (M-CLL) and unmutated IGHV genes (U-CLL) typically have a favourable and poorer prognosis, respectively [1, 2].