The potential role of antigens in the pathogenesis of CLL is further supported by the presence of the non-stochastic pairing of IGHV, IGKV and IGLV genes, which leads to nearly identical BCR sequences of heavy chain complementarity determining region 3 (HCDR3) region, described as “stereotyped” BCR, in about 30% of Caucasian CLL [28]. This evidence concerns the gene BCR and B-cell chronic lymphocytic leukemia.