WT1 is an integral component of an antibody panel to distinguish pancreaticobiliary and some ovarian epithelial neoplasms

We investigated whether a panel of antibodies including WT1 could separate pancreaticobiliarv and ovarian carcinomas by staining 64 pancreaticobiliary adenocarcinomas, 41 ovarian serous carcinomas, and 12 primary ovarian muci nous neoplasms with WT1, cytokeratin (CK) 17, CK20, carcinoembryonic antige n (CEA), and CA-125. Moderate or strong intensity reactivity, in more than 25% of cells was a positive result. Of the ovarian serous carcinomas, 38 (9 3%) were WT1 reactive and 22 (54%) WT1 positive, 9 (22%) had CK20 reactivit y, and 3 (7%) were CK20 positive in fewer than 50% of cells. All were CK17 or CEA nonreactive. Of the ovarian mucinous neoplasms, all were WT1 and CK1 7 nonreactive and 11 (92%) were CEA reactive, 8 (67%) CEA positive, 10 (83% ) CK20 reactive, and 6 (50%) CK20 positive. Of the pancreaticobiliary adeno carcinomas, 19 (30%) were CK20 positive, 27 (42%) CK17 positive, and 52 (81 %) CEA positive. All were WT1 nonreactive. A panel including WT1, CK17, CK2 0, and CEA is useful to distinguish pancreaticobiliary and ovarian serous c arcinomas. Extensive CK17 reactivity is supportive of a pancreaticobiliary adenocarcinoma when the differential diagnosis includes ovarian mucinous ne oplasm. None of the antibodies positively identified ovarian Mucinous neopl asms.