Relationship of the epidermal growth factor-receptor to the growth fraction (Ki-67 antibody) and the flow cytometric S-phase as cell kinetics parameters, in human mammary carcinomas.

Epidermal growth factor (EGF) has been shown to have a mitogenic effect on some breast cancer cells lines in vitro. The growth of the subclass of human breast tumors which expresses the specific receptor for EGF seems to be mediated by autocrine mechanisms rather than steroid hormones. The expression of EGF-receptor, as detected by an immunocytochemical method, was compared with the Growth Fraction (GF) by the Ki-67 monoclonal antibody and the S-phase content as tumor proliferative activity indexes, and with DNA ploidy and some pathologic features in 86 stage I-II breast carcinomas. Overall 52 out of 86 (60%) of the tumors were EGF-receptor positive. There was no correlation between the cell kinetics parameters and the EGF-receptor status, suggesting that its expression may be unrelated to the proliferative activity of the tumor in these clinical stages and that the EGF-receptor GF and S-phase may be independent variables in breast cancer. In our series 57% of tumors were DNA aneuploid and only a trend was found towards EGF-receptor positivity (P = 0.08). There was no correlation between EGF-receptor expression and grading or node-status. The overall picture is that of an independent relationship between EGF-receptor with the cell kinetics parameters and ploidy, confirming the complex and heterogeneous biology of breast carcinoma. These results suggest the possibility of better recognition of subsets of patients with diverse tumor aggressiveness, combining together EGF-receptor status, cell kinetics and ploidy, with a better stratification for treatment options.