Cytokeratin 34bE12 antibody recognizes cytokeratin 1, 5, 10, and 14 in the Moll catalog (MW 68kDa, 58kDa, 56.5kDa, and 50kDa), respectively. Cytokeratin 34bE12 antibody promises to be a specific marker useful in differential identification of squamous carcinomas from adenocarcinomas and differential diagnosis of benign and malignant tumors of prostatic gland. In normal cells, it labels squamous, ductal and other complex epithelia. It reacts with benign small-acinar lesions of the prostate and does not react with hepatocytes, pancreatic acinar cells, proximal renal tubes or endometrial glands. In tumor cells, this antibody is reactive with both squamous and ductal neoplasms and variably with those derived from simple epithelium.