POU5F1 and prostate intraepithelial neoplasia: Immunohistochemical analysis confirmed the diagnosis of metastatic prostate adenocarcinoma of the ductal type, with positive staining for cytokeratin AE1/AE3, epithelial membrane antigen, PSA, and prostatic intraepithelial neoplasia marker (PIN), and negative staining for cluster of differentiation 30, cluster of differentiation 117, vimentin, octamer-binding transcription factor 4 (OCT-4), placental alkaline phosphatase (PLAP), and HCG.