CDKN2A and B-cell chronic lymphocytic leukemia: A stable RT cell line established from the cervical lymph node of a 60-year-old patient with CLL and clonally-related RT-DLBCL revealed a complex karyotype with the loss of TP53 and CDKN2A, a chromosomal gain of the NOTCH1 gene locus, and strong immunoreactivity for BCL-2 [50].