BerEp4 has a high sensitivity and specificity in being positive only in BCC cells.[1] BerEp4 is normally negative in squamous epithelium and mesothelium, but otherwise normally positive most epithelial cells of the body.[3] It can also help in distinguishing pulmonary adenocarcinoma (positive BerEp4) from mesothelioma (generally negative BerEp4).[3][4]