PMAIP1 and neoplasm: The BH3-only proteins, which are regulated by multiple mechanisms, mediate the responses to various cytotoxic insults.23, 24 For example, whereas DNA damage upregulates p53 protein, which induces expression of PUMA and NOXA, cytokine deprivation relies mainly on BIM and PUMA.23 Just as the pro-survival proteins are oncoproteins, several BH3-only proteins can be tumour suppressors.23, 24, 25