%0 Journal Article %T Diagnostic utility of p63/P501S double sequential immunohistochemical staining in differentiating urothelial carcinoma from prostate carcinoma %A Malini Srinivasan %A Anil V Parwani %J Diagnostic Pathology %D 2011 %I BioMed Central %R 10.1186/1746-1596-6-67 %X p63/P501S dual-color sequential immunohistochemical staining was performed on archival material from 132 patients with high-grade UC and 23 patients with PC, and evaluated for p63 (brown nuclear) and P501S (red cytoplasmic) expression. Both the staining intensity and percentage of positive tumor cells were assessed.p63 was positive in 119/132 of UC and negative in PC. P501S was positive in 22/23 of PC and negative in UC. The p63+/P501S- immunoprofile had 90% sensitivity and 100% specificity for UC. The p63-/P501S+ immunoprofile had 96% sensitivity and 100% specificity for PC.Our results indicate that double sequential immunohistochemical staining with p63 and P501S is highly specific and can be a useful tool in distinguishing UC from PC especially when there is limited diagnostic tissue as it can be performed on a single slide.Distinction between prostate carcinoma (PC) and urothelial carcinoma (UC) is important due to the potential therapeutic and prognostic implications. Whereas hormone therapy may be used in treatment of PC, chemotherapy is used for UC. However, discriminating between these two cancers can be a diagnostic challenge especially in high grade tumors and in the presence of limited tissue. Immunohistochemistry, using both established and newer markers, is often used as a diagnostic tool in identifying the prostatic or urothelial origin of tumors.Among the markers used to distinguish between urothelial and prostate cancers, prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PSAP) are most commonly used to establish the prostatic origin of tumors; however, their expression is significantly decreased in poorly differentiated prostatic cancers [1,2]. Among the newer markers, prostate-specific membrane antigen (PSMA) and P501S (prostein) have been shown to have excellent specificity in differentiating prostate from urothelial cancers [3]. While alpha-methylacyl-CoA-racemase (AMACR), also known as P504S, is a useful biomarker of prostat %U http://www.diagnosticpathology.org/content/6/1/67