We have previously reported the concentration-dependent cytotoxic effect of the second-generation small-molecule inhibitor of the p53–MDM2 interaction, idasanutlin (RG7388), on ex vivo-tested TP53WT primary chronic lymphocytic leukemia (CLL) patient samples, when compared with normal hematopoietic and bone marrow cells, and TP53MUT CLL cells [2]. This evidence concerns the gene TP53 and B-cell chronic lymphocytic leukemia.