Is triple immunostaining with 34betaE12, p63, and racemase in prostate cancer advantageous? A tissue microarray study.

This study aimed to determine the usefulness of a combination of 3 immunohistochemical markers, 34/betaE12, p63 and alpha-methylacyl coenzyme A racemase (AMACR), for the diagnosis of prostate cancer using tissue microarrays (TMAs) constructed from 91 archival radical prostatectomy specimens derived from the Pathology Department files of Singapore General Hospital, Singapore. Triple immunostaining using a cocktail of these 3 antibodies was performed on TMA sections using the streptavidin-biotin method. When compared with immunohistochemical staining using the individual antibodies, we found that the triple cocktail allowed improved evaluation of basal cells in benign glands, and AMACR allowed simultaneous corroboration of malignant prostatic glands in the same section. We achieved a specificity of 100% with the triple cocktail, and sensitivity was acceptable, at 93.8%. In comparison, specificity and sensitivity of the individual antibodies were 95.5% and 97.3%, 93.3% and 93.8%, 97.0% and 95.6% for p63, 34betaE12, and AMACR, respectively. The triple cocktail offers a cost-effective way of evaluating abnormal prostatic glandular foci, in addition to maximizing the use of small tissue samples from prostatic needle biopsies.