This antibody labels the Alpha Methylacyl Coenzyme A Racemase (AMACR) protein in the cytoplasm of epithelia in both normal and neoplastic cells.  AMACR is positive in cells of premalignant high-grade prostatic intraepitheliam neoplasia and prostate adenocarcinoma, but is present at low or undetectable levels in glandular epithelial cells of normal prostate and benign hyperplasia.  It is a useful tool for identifying prostate cancer when used in a panel of antibodies.