The distribution of carcinoembryonic antigen in breast carcinoma. Diagnostic and prognostic implications.

Carcinoembryonic antigen (CEA) has been shown to be a useful tumor marker in patients with breast carcinoma. The unlabeled antibody immunoperoxidase technique was used to localize CEA in 93 cases of primary breast carcinoma, 15 cases of atypical duct papillomatosis, and 4 cases of duct papilloma. Normal breast epithelium and breast epithelium in fibrocystic disease did not stain positively for CEA. Twenty-four of 27 (88%) intraductal carcinomas, and 47 of 69 (68%) infiltrating duct carcinomas were CEA positive. In contrast, only 5 of 21 (23%) in situ lobular carcinomas and 8 of 24 (33%) infiltrating lobular carcinomas were positive for CEA. All 15 cases of atypical epithelial papillomatosis were negative, whereas 1 of the 4 cases of duct papilloma exhibited microscopic foci of weak CEA positivity. There was a trend for infiltrating duct carcinomas, 3 cm in diameter or smaller, staining strongly positive for CEA, to be associated with synchronous axillary lymph node metastases (P = 0.09). Tumor heterogeneity was a constant feature of CEA staining with positivity varying from region to region and even from cell to cell. Positive immunohistochemical staining for CEA may play an adjunctive role in discriminating intraductal carcinoma from atypical papillary ductal proliferations.