AMACR/P504S is a mitochondrial and peroxisomal enzyme that is overexpressed in prostate cancer and premalignant prostatic lesions including intraepithelial neoplasia and atypical adenomatous hyperplasia. AMACR overexpression has also been detected in a number of other cancers including ovarian, breast, bladder, lung, and renal cell carcinomas, lymphoma, and melanoma. AMACR functions to oxidize fatty acids, drugs such as ibuprofen, and bile acid intermediates. It is broadly expressed in normal tissues such as kidney and liver, with a cytoplasmic distribution. AMACR is positive in prostate carcinoma and negative or weak in normal or hyperplastic prostate. References: The American journal of surgical pathology. 2001. 25.11: 1397-1404, PMID: 11684956 ; Urology. 77 (1): 249.e1–7, PMID: 21195844; Am. J. Surg. Pathol. 27 (6): 772–8, PMID: 12766580.