TP53 and neuroblastoma: However, caspase 2 can trigger apoptosis also in a p53-independent manner, through release of pro-apoptotic factors (such as BID or BAX) from mitochondria.71 It is therefore possible that this pathway contributes to PLK4i cytotoxicity in neuroblastoma when p53 is inactivated, which is consistent with our CRISPR screen observations.