Tumor Associated Glycoprotein 72 (TAG-72) is common to most epithelial tumors. In this study serum levels of TAG-72 were measured in 36 healthy female subjects, in 94 patients with breast cancer, and in 43 others with epithelial ovarian cancer. More particularly, 27 out of the 94 patients with breast cancer had early disease (Stage I-I; or T 0-2b; N 0-1b; M 0), while the remaining 67 had advanced disease (Stage III-IV; or T 0-4; N 0-3; M 0-1). All the 43 subjects with ovarian cancer were at stage III-IV (FIGO Classification), 12 of whom had minimal disease (lesions less than 2 cm) and the other 31 had bulky disease. 3.5 U/ml being the highest value found in the control group, we arbitrarily assumed 3.85 U/ml (mean +/- 3 SD) as the cut-off limit in this preliminary study. Among the patients with breast cancer, 17 out of the 67 subjects with advanced disease (25.3%) and 1 out of the 27 others with early disease (3.7%) exceeded the TAG-72 cut-off limit. Among the patients with ovarian cancer, 2 out of the 12 subjects with minimal disease (16.7%) and 22 out of the others 31 with bulky disease (70.9%) had TAG-72 levels above cut-off limit. High TAG-72 levels were found in all the histotypes of ovarian cancer including the mucinous type. Preliminary data seem to indicate that in ovarian cancer variations in serum levels of TAG-72 are in agreement with the trend of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)