This antibody recognizes CK1, CK5, CK10 and CK14. In normal epithelia, it stains stratified epithelia, myoepithelial cells and basal cells in the prostate gland and bronchi. This MAb shows no reactivity with hepatocytes, pancreatic acinar cells, proximal renal tubules, or endometrial glands; there is no reactivity with cells derived from simple epithelia. Mesenchymal tumors, lymphomas, melanomas, neural tumors, and neuroendocrine tumors are negative with this antibody. It stains myoepithelial cells and has been shown to be useful in distinguishing prostate adenocarcinoma from benign prostate. This antibody has also been useful in separating benign from malignant intraductal breast proliferations.