P504S has been recently described as a prostate cancer-specific gene that encodes a protein involved in the β-oxidation of branched chain fatty acids. Expression of p504S protein is found in prostatic adenocarcinoma but not in benign prostatic tissue. It stains premalignant lesions of prostate: high-grade prostatic intraepithelial neoplasia (PIN) and atypical adenomatous hyperplasia. P504S can be used as a positive marker for PIN.

p504s overexpression has also been detected in a number of other cancers including ovarian, breast, bladder, lung, and renal cell carcinomas, lymphoma, and melanoma.