Subset #2 includes patients with CLL expressing BcR IG encoded by the IGHV3-21/IGLV3-21 genes with distinctive, restricted VH and VL CDR3 sequences [1, 47–50], of whom the majority (~60–65%) carry somatically hypermutated IGHV genes. The gene discussed is BCR; the disease is B-cell chronic lymphocytic leukemia.