Taken together, these insights on ASCL1 versus NEUROD1 expression within NEPC and SYP expression in PRAD argue for a standardized IHC panel–based approach using ASCL1, NEUROD1, INSM1 and SYP, in conjunction with histomorphological assessment, to add greater precision to the diagnosis and treatment of NEPC. The gene discussed is SYP; the disease is prostate adenocarcinoma.