BCL2L11 and mantle cell lymphoma: In particular, most tumours (~90%) have mutations that inactivate the p53 protein, delete its gene or impair upstream regulators, preventing p53 induction of PUMA and NOXA to drive apoptosis.64 In addition, 17% of mantle cell lymphoma cell lines have homozygous deletions of BIM,65 and many Burkitt lymphomas harbour epigenetically silenced BIM or PUMA alleles.66, 67