An Optimal Immunohistochemical Panel to Distinguish Poorly Differentiated Prostate Adenocarcinoma From Urothelial Carcinoma

An optimal immunohistochemical panel to distinguish poorly differentiated prostate (PCa) from urothelial (UCa) carcinoma was selected from a panel consisting of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), high-molecular-weight cytokeratin (HMWCK) (clone 34βE12), cytokeratin (CK) 7, CK20, p63, and α-methylacyl-coenzyme A racemase. The pilot group was composed of poorly differentiated UCa (n = 36) and PCa (n = 42). PSA and PAP stained 95 % of PCa vs 0 % and 11% of UCa cases, respectively. HMWCK and p63 stained 97 % and 92 % of UCa vs 2 % and 0 % of PCa cases respectively. CK7/CK20 coexpression was noted in 50 % of UCa cases, whereas 86 % of PCa cases were negative with both. A panel of PSA, HMWCK, and p6