Occurrence of carcinoembryonic antigen in tumor tissue and serum of breast cancer patients.

In 116 breast cancer patients, the levels of carcinoembryonic antigen (CEA) were determined before operation in the serum using RIA, and after operation in sections of breast tumor tissue using the immunohistological PAP technique. CEA circulating in the serum was found in 49 patients (42%). Elevated values (over 10 micrograms/l) were found in only 12 patients (10%). In histological specimens CEA positivity was found in 94 tumors (81%), however, in a majority of them the number of positive cells per section was low (1-10%). A comparison of positive and negative findings both in the serum and in the tumor specimens of individual patients showed that both serum and tumor sections were CEA positive in 40 patients (35%) and both localizations were CEA negative in 13 patients (12%). Although most patients had positive histological sections but negative sera (46%). Only 7% of patients had negative sections and positive sera. In 41 patients CEA could be examined both qualitatively (immunohistologically), and quantitatively in the cytosol of the same homogenized tumor. Of them, 30 patients (72%) had in the cytosol a CEA concentration exceeding 5 micrograms/g proteins, in 11 of the 41 patients (28%) no CEA was found. Immunohistological examination of CEA in this group gave positive results in 35 out of the 41 patients (85%), and only 6 tumors (15%) were completely negative. CEA was shown to be present in each histological type of the tumors studied, invasive ductal tumors being slightly more frequent and more positive than the lobular ones. No relation was observed to the structure of the tumors, nor to the degree of their differentiation. Thus, the examination of CEA levels can hardly contribute to the improvement of histological classification.