It is desirable to identify the tumoric factors anticipating the therapeutic failure in breast cancer patients received postoperative adjuvant chemotherapy. So, we studied the tumoric topoisomerase IIα enzyme, c-erbB-2 oncoprotein, and Pgp expression in breast cancer tissues to identify the roles of these factors as the predictors of chemotherapeutic result. The results were as follows. 1) There were no significant differences in the average value of topoisomerase IIα enzyme, c-erbB-2 oncoprotein overexpression, and Pgp expression according to stages. 2) CAF chemotherapy was suggested to be more effective than CMF chemotherapy in more advanced stages. 3) There was a possible suggestion that the breast cancer with high topoisomerase IIα enzyme activity might indicate the failure with CMF chemotherapy. 4) C-erbB-2 oncoprotein overexpression suggested the possibility of therapeutic failure with CMF chemotherapy and the selection of CAF chemotherapy might improve the survival of advanced breast cancer patients with c-erbB-2 overexpression, In conclusion, it was suggested that c-erbB-2 oncoprotein overexpression and high topoisomerase IIα activity might have a meaningful role in the selection of proper chemotherapeutic regimen in setting of adjuvant chemotherapy and predict the therapeutic failure of some chemotherapeutic agents for breast cancer. An expanded study for these factors is required to reveal the clinical significance in chemotherapy for breast cancer patients.