TP53 and neoplasm: The main evidence for a sequence-specific transactivation (SST)-independent pathway for p53-induced apoptosis comes from Mihara et al., who demonstrated that bypassing the nucleus by targeting p53 to the mitochondria (via fusion with a mitochondrial import leader peptide, designated L-p53) was sufficient to launch apoptosis in p53-deficient tumor cells (9) and to suppress colony growth, although not as strongly as nuclear p53.