It is associated with pathogenesis and outcome of B-CLLs: monoallelic deletion slower growth kinetic than biallelic [164] due to the directly targeting of TP53 [166] and consistent with indolent B-CLL and more favourable prognosis than 17p13 or 11q23 deletions [90]. In addition targets BCL2, MCL1 and CDK6 [165]. This evidence concerns the gene BCL2 and B-cell chronic lymphocytic leukemia.