CLL may be classified based on mutational status of the immunoglobulin variable heavy-chain gene, ZAP-70 overexpression, cytogenetic abnormalities (13q-, + 12, 11q-, 17p-) and expression of several cell surface antigens (CD38, CD49d) that correlate with risk of disease progression (Rai or Binet staging system) [61]. This evidence concerns the gene CD38 and B-cell chronic lymphocytic leukemia.