TP53 and B-cell chronic lymphocytic leukemia: The presence of del(17p) and/or abnormal p53 function have consistently been shown to identify CLL patients whose responses to purine nucleoside analogs and alkylating agents are short-lived.13–14,17–18 Patients with 17p deletions experience treatment-free intervals of only 9 months and PFS intervals of 11 months after fludarabine based chemotherapy.13–14 The molecular basis for this clinical observation is disruption of p53-dependent apoptosis, responsible for the anti-leukemic effect of purine analogs and alkylating agents, in patients with del(17p13).