OBJECTIVETo investigate the value of using an AMACR/34betaE12/p63 cocktail and double-staining for the diagnosis of small focal protatic carcinoma and precarcinomatous lesions.

METHODSA total of 130 consecutive cases were examined over a 3-month period, including 105 prostate needle biopsy samples, 6 radical prostatectomy specimens and 19 benign prostatic hyperplasia specimens which were excised transurethra or above pubis. 262 paraffin blocks of all the 1030 ones were stained with hematoxylin and eosin and by immunostains for AMACR, 34betaE12, p63, and an antibody cocktail comprising all the three with double-chromogen reaction. The diagnoses were then made according to the immunostaining, HE staining and clinical information.

RESULTSIn the sections stained by the 3-antibody cocktail, blue-black cytoplasmic staining was observed in the epithelial cells of prostatic carcinoma and high-grade prostatic intraepithelial neoplasia (HGPIN) the basal cells of benign glands were stained red. There were no red basal cells around the blue-black glandular epithelium of carcinoma, but discontinuous or consecutive red basal cells were present around the blue-black glandular epithelium of HGPIN. Prostatic carcinoma was found in 214 paraffin blocks (82%), including 31 small focal carcinoma. HGPIN were observed in 64 paraffin blocks (24%), including focal HGPIN and small gland alveolus HGPIN. AAH was found in one block. No benign glands were simultaneously positive for AMACR and negative for basal cell markers.

CONCLUSIONInmmunohistochemistry studies using a 3-antibody cocktail and double staining can improve the detection rate of small focal prostatic carcinoma and HGPIN.