THE APPLICABILITY OF A KERATIN 7 MONOCLONAL-ANTIBODY IN ROUTINELY PAPANICOLAOU-STAINED CYTOLOGIC SPECIMENS FOR THE DIFFERENTIAL-DIAGNOSIS OF CARCINOMAS

The monoclonal antibody OV-TL 12/30, which detects keratin 7, was test ed for its usefulness in cytologic diagnosis by reincubating previousl y Papanicolaou-stained slides. For this purpose malignant effusions of 73 patients with histologically confirmed cancers of the colon, ovary , mesothelium, breast, lung, esophagus, pancreas, urinary bladder, sto mach, kidney, and prostate were used. All malignant cells from ovarian adenocarcinomas were positive, whereas malignant cells from colonic a denocarcinomas and malignant mesotheliomas were negative. Adenocarcino mas of gastric, renal, pancreatic, esophageal, and mammary origin demo nstrated variable staining. Transitional cell carcinomas were positive , whereas squamous and small cell lung carcinomas were negative. Becau se OV-TL 12/30 does not react with normal and atypical mesothelial cel ls in these preparations, this reagent is a valuable tool in distingui shing benign mesothelial cells and adenocarcinoma cells. The authors' results demonstrate that this antibody is an excellent tool in the dif ferential diagnosis of malignant cells in effusions and can be used in routinely stained cytologic specimens to determine primary tumor loca lization. In addition to its ability to distinguish between ovarian an d colonic adenocarcinomas, its negativity in mesotheliomas may prove h elpful in several diagnostic considerations.