DLL3 and large cell neuroendocrine carcinoma: Neuroendocrine carcinomas (NEC) are a group of poorly differentiated neuroendocrine neoplasms3 that commonly express DLL3, with positive DLL3 expression observed in 65–74% of large cell NEC and in 77% of castration-resistant neuroendocrine prostate cancer (NEPC)6,7.