THE UTILITY OF BASAL CELL-SPECIFIC ANTI-CYTOKERATIN ANTIBODY (34-BETA-E12) IN THE DIAGNOSIS OF PROSTATE-CANCER - A REVIEW OF 228 CASES

Basal cell-specific anti-cytokeratin antibody (34 beta 12) decorates t he basal cells of benign prostatic epithelium by standard immunohistoc hemical techniques, whereas adenocarcinoma of the prostate lacks immun oreactivity with this antibody. We reviewed our experience with this a ntibody to determine its utility in the diagnosis of adenocarcinoma of the prostate as well as its pattern of usage at a tertiary medical ce nter. In all, 7,242 prostate specimens from 5,262 men were seen at Joh ns Hopkins Hospital between 1/89 and 4/93. Immunostaining for basal ce ll-specific cytokeratin (34 beta 12) was originally used for diagnosti c purposes in 289 questionable areas from 228 cases; 45% of these case s were seen in consultation. The distribution of cases using 34 beta E 12 was 52% needle biopsies, 32% transurethral prostatic resections (TU RPs), 13% radical prostatectomies, and 3% open enucleations. These pro cedures constituted 2.8% of all needle biopsies, 7.2% of all TURPs, 1. 7% of all radical prostatectomies, and 3.5% of all enucleations seen d uring this time period. For this study the hematoxylin and eosin stain was reviewed without knowledge of the original diagnosis, a diagnosis was favored, the 34 beta E12 stain was examined, and a final diagnosi s was determined. The 34 beta E12 stain established (14%), confirmed ( 58%), or changed (2%) our favored diagnoses, while 18% remained or bec ame equivocal. The 34 beta E12 stain was of no use in 8% of the cases, yet we felt we were still able to render a final diagnosis even witho ut the help of the stain. The differential diagnoses in the questionab le foci using 34 beta E12 were cancer versus focus of atypical glands (44%), adenosis (39%), prostatic intraepithelial neoplasia (PIN) (8%), basal cell hyperplasia (5%), and atrophy (4%). However, 34 beta E12 w as used in only 15-20% of all cases of adenosis and basal cell hyperpl asia and in <2% of PIN and atrophy cases seen during this time. Reason s for equivocal results were loss of suspicious glands on cut downs us ed for staining (49%), too few glands to rely on negative staining (23 %), technical problems (15%), limited number of positive staining glan ds in a small focus (7%), and cautery artifact (6%). Although equivoca l cases tended to have fewer negative stained glands than cases diagno sed with cancer, there was no minimum number of negative stained gland s required to establish a diagnosis of cancer. From these data we conc lude that 34 beta E12 staining is a useful tool in confirming, establi shing, or changing the diagnosis in questionable foci seen in the ever yday practice of surgical pathology. We feel that it is most useful in the workup of foci of atypical glands on needle biopsy and in differe ntiating low-grade adenocarcinoma from adenosis on TURF. Staining with 34 beta E12 is a cost-effective means to work up a needle biopsy as c ompared with ultrasound-guided re-biopsy.