BCR and B-cell chronic lymphocytic leukemia: Two major molecular subtypes of CLL are recognized based on the molecular configuration of the B cell receptor immunoglobulin (BcR IG), more particularly the somatic hypermutation (SHM) status of the IGHV genes: cases with no or minimal SHM (‘IG-unmutated’ CLL, U-CLL) follow considerably more aggressive clinical courses compared to those with a significant SHM load (‘IG-mutated’ CLL, M-CLL) (29–31).