CA-125 (MUC16) is a mucin glycoprotein expressed by epithelial cells of endometrium, endocervix, pleura, pericardium, and fallopian tube peritoneum. Antibodies to this target are useful for identifying non-mucinous epithelial ovarian carcinomas, serous and endometrioid adenocarcinomas, Krukenberg tumors, and uterine leiomyomas. Elevated levels of serum CA-125 are correlated with the presence or recurrence of ovarian cancer. In immunohistochemistry, MUC16 is positive in the apical brush border of the fallopian tube epithelium, serous ovarian adenocarcinomas and mesotheliomas. It is negative in melanoma, lung and other adenocarcinomas. References: Clin Onc 12:437, 2015; International Journal of Cancer. 2002. 98 (5): 737–40. doi:10.1002/ijc.10250, PMID: 11920644; Expert Review of Molecular Diagnostics. 2010. 10 (8): 1069–83, PMID: 21080822.