TP53 and small cell carcinoma: The p53 signaling has been proposed to act in preventing the expansion of a small number of neuroendocrine (NE) lineage cells that reside in the mass of hormone-sensitive prostate carcinoma; and upon TP53 mutation, this small subpopulation of NE cells propagates to form a rare, clinically different subtype of CRPC (small cell neuroendocrine carcinoma)39.