TP53 and B-cell chronic lymphocytic leukemia: By applying a training/validation strategy using a cohort of 140 CLL cases with known TP53 status, we propose a short term in vitro functional assay, based on the exposure of CLL cells to the non-genotoxic TP53 activator Nutlin-3, as a tool to identify CLL cases with dysregulated TP53 in a clinical setting.