EMA is a transmembrane glycoprotein with a molecular weight of 400 kDa that is widely distributed in epithelial cells and tumors of epithelial origin. Anti-EMA antibodies are a useful marker for staining many carcinomas. It stains normal and neoplastic cells from various tissues, including mammary epithelium, sweat glands and colorectal carcinoma. Hepatocellular carcinoma, adrenal carcinoma and embryonal carcinoma are consistently EMA-negative, so keratin positivity with negative EMA is suggestive of one of these tumors. EMA is often positive in meningiomas, which may be useful in distinguishing them from other intracranial neoplasms such as schwannomas.