Immunohistochemical staining (IHC) of a total of 86 specimens (including 17 of those studied by ISH) localized NEU antigen expression to epithelial cells in 36 of 86 samples with strong membrane staining observed in 12, including 1 benign, 1 borderline serous carcinoma, 3 clear cell/endometrioid carcinomas, and 7 predominantly papillary serous carcinomas with areas of clear cell/endometrioid histology.