The analysis of VH CDR3 in more than 7000 VH (IGHV-IGHD-IGHJ) sequences from patients with CLL has established that CLL comprises two distinct categories: one with stereotyped and the other with heterogeneous BCR, in an approximate ratio of 1:2 [27]. The gene discussed is BCR; the disease is B-cell chronic lymphocytic leukemia.