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 will 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.
p63 encodes for different isotypes able
to either transactivate p53 reporter genes (TAp63) or act as
p53-dominant-negatives. P63 is detected in prostate basal epithelial nuclei in
normal prostate, however, is negative in malignant tumors of the prostate gland.
Thus p63 is useful as a differential marker for benign and malignant tumors of
prostate gland and can be useful as a negative marker.
The combination of P504S and p63 (PIN)
may be extremely useful for diagnosing prostatic intraepithelial neoplasia
(PIN), especially in difficult and limited tissues cases. This antibody may
eliminate the need for HMW CK [34ßE12]. P504S stains cytoplasm in prostate
adenocarcinoma and atypical adenomatous hyperplasia; p63 stains nuclei in normal
(negative marker) and benign prostate glands. In this instance, the PIN
combination becomes a double stain procedure. (A goat antimouse and rabbit
universal detection kit must be used.)