Breast cancer is supposed that its biological behavior should be changed in some relationship with the advancement of tumor. P-glycoprotein is the well-known nuclear protein which shows multiple drug resistance, and its expression means the resistance to various chemotherapeutic agents including anthracyclines. Angiogenesis was also suggested to have an important role in tumor progression and metastasis, which has been considered to be one of valuable independent prognostic factors. Tumor proliferative activity also has been thought to be very useful as a factor representing the biological behavior of tumor, but its role isn't fully understood yet. In this study we aimed to observe how these factors are expressed with any relationship according to the tumor stage and to find the feature of its expression in each stage and its clinicopathologic significances.

62 cases of patients histologically proven into invasive ductal carcinoma, who were diagnosed and treated at the Department of Surgery, Chonnam National University Hospital, were selected. In order to estimate the stainng results accurately, we classified the expression grades of Pgp into 5 classes according to the count of immunostained cells after immunohistochemical staining. Angiogenesis was determined by the mean count of microvessels measured by image analyzer moving more than 40 fields with 200 folds magnification after immunohistochemical staining for CD34. Tumor proliferative activity were presented in percentage by counting the positively immunostained cells in more than 500 tumor cells after imunohistochemical staining with Ki67. Statistical evaluation was done by Mann-Whitney test and we determined that the result showing p-value less than 0.05 is statistically significant.

The mean age was 49 years(from 33years to 82years) and the stage distribution was stage I: 4 patients, stage IIa: 25, stage IIb: 18, stage IIIa: 7, stage IIIb: 3, and stage IV: 5 patients. In spite of Pgp expression tended to increase as the stage advanced, it did not show any statistically significant difference(p-0.165). Ahhough Ki67 score representing tumor proliferation activity was observed from 0% to 30.8%, any significant differences according to advancement of Stage were not found(p-0.850). Tumoric angiogenesis also did not show any statistical difference according to advancement of stage(p-0.189).

We could nol fmd any significant proportional correlationship between the tumor stage and Pgp expression, tumor proliferative activity, and angiogenesis. 1nerefore, the clinicopathologic significances of these factors are supposed to determine an individual biological feature of the tumor irrespective of stages.