Evaluation of p63 Immunohistochemical Stain as First Line Marker in Differentiating Urothelial Carcinomas from Adenocarcinomas of Prostate

Abstract

BACKGROUND Differentiating prostate carcinoma (PCa) arising in the neck of urinary bladder from high grade urothelial cancer (UCa) with prostatic extension can be a difficult task for histopathologist due to similar morphologic characteristics and overlapping clinical manifestations in the two diseases. These two tumours often occur in association with one another but have different potential therapeutic strategies and prognostic implications. We have investigated p63 immunohistochemical (IHC) marker as simple first line marker adjuvant to histopathological examination. METHODS In this prospective study, total 50 cases including 25 cases of urothelial carcinoma and 25 cases of prostatic carcinoma were taken. Tumour grade was determined according to standard H&E staining and scoring system. p63 expressions were determined by immunohistochemical staining of all the cases. The obtained results were analysed and evaluated using chi-square statistical test to determine whether p63 IHC can be used as simple first line marker tool with a high sensitivity and specificity. RESULTS p63 was not expressed in any of the 25 cases of prostatic carcinoma cases while in urothelial carcinoma it was expressed in 23 of 25 (92 %) cases. p63 IHC staining expression is positive in all histological grades of urothelial carcinomas. 2 out of 25 cases of urothelial carcinomas were negative for p63 IHC expression. None of the prostatic adenocarcinomas expressed p63 staining. Sensitivity of p63 stain in differentiating UCa with PCa was 92 % in our study, specificity of p63 stain in differentiating UCa with PCa was found to be 100 %. CONCLUSIONS p63 can be used as a screening first line IHC marker to distinguish urothelial carcinomas from prostatic adenocarcinomas. For challenging and unresolved cases both of these have limited sensitivity; thus, authors recommend two lineagespecific markers one each for UCa (GATA3, S100P) and PCa (NKX3.1, P501S, PSMA) should be used for definitive diagnosis. KEYWORDS p63 Immunohistochemistry, Urothelial Carcinoma, Prostatic Adenocarcinoma