Diagnostic utility of alpha-methylacyl CoA racemase (P504S) on prostate needle biopsy.

Alpha-methylacyl CoA racemase (AMACR), also known as P504S, was identified by the analysis of cDNA library subtraction in conjunction with high throughput microarray screening from prostate tissue and has been proven to be one of the very few biomarkers that can distinguish cancer from benign cells with high sensitivity and specificity for prostate carcinoma. It is a successful example of the translation of molecular findings into clinical practice. This review focuses on the study of AMACR (P504S) expression in small focal prostate cancer and atypical small acinar proliferation (ASAP) on needle biopsies and emphasizes the utility of AMACR (P504S) in routine surgical pathology practice. We also discuss the potential pitfalls and caveats in the interpretation of immunostaining results.