α-Methylacyl-CoA racemase 1 is an enzyme that catalyzes a critical chiral conversion step in the metabolism of branched-chain fatty acids and serves as a marker for prostate and other cancers.

α-methylacyl-CoA racemase protein levels are elevated in all prostate and certain other cancer cells, making it useful as a marker. This enzyme functions without cofactors, facilitating reaction through stepwise 1,1-proton transfer via an enolate intermediate. Its role in cancer is intricate, linking lipid metabolism with nuclear receptor (e.g., FXR and PPAR) activity and the expression of enzymes like cyclooxygenase-2 (COX-2). α-methylacyl-CoA racemase 1 aids in confirming prostate cancer diagnosis, particularly when paired with basal cell markers. Microarray analysis shows high AMACR expression in tumors such as prostate adenocarcinomas (72%), hepatocellular carcinomas (77%), papillary renal cell carcinomas (70%), and colorectal adenocarcinomas (71%).