Prognostic significance of the combination of biological parameters in breast cancer.

To evaluate whether the combination of biological parameters increases their prognostic value, the expression of epidermal growth factor receptor (EGFR), DNA ploidy, and estrogen receptor (ER) status were analyzed on 998 patients with breast cancer. Poor findings for each biological parameter were positive for EGFR, aneuploid for DNA ploidy, and negative for ER. According to the number of poor findings in these three parameters, the groups with none (309 cases), one (377 cases), two (161 cases), and three (151 cases) poor findings were classified. A significant ( P < 0.0001) difference was found in the disease-free survival (DFS) among the four groups. A multivariate analysis indicated the combination of three biological parameters to be an independently significant factor for DFS, while the relative risk gradually increased as the number of poor findings increased. In conclusion, the present study indicated a gradual increase in the prognostic significance as the number of combined biological parameters increased.