P504S
is an enzyme in the ß-oxidation of branched-chain fatty acids. Expression of
P504S protein is found in prostatic adenocarcinoma but not in benign prostatic
tissue. It has also been found to stain premalignant lesions of the prostate:
high-grade prostatic intraepithelial neoplasia (PIN) and atypical adenomatous
hyperplasia. P504S can be used as a positive marker for PIN. It may be useful to
confirm the diagnosis of small foci of prostate carcinoma in needle biopsies.
P504S stains the majority prostate cancer, however, P504S has been shown to
stain many other types of carcinoma such as hepatoma, breast carcinoma,
pancreatic islet tumor and desmoplastic small round cell tumor (Miller and
Tacha)1. HMW CK and p63 may serve as a useful
panel.