CDKN1B and B-cell chronic lymphocytic leukemia: However, it seems advisable to devise a study aimed at determining whether polymorphisms of the CDKN1B and CCND2 genes have an impact on the efficacy of the different regimens currently used in CLL (Bruton’s tyrosine kinase inhibitors, inhibitors of BCL2 protein, anti-CD20 monoclonal antibodies).