The aim of this study was the analysis of Ki-67, Bcl-2 and Bak expression in primary
tumor and axillary
lymph node metastases of
breast cancer as well as an attempt to assess preoperative
chemotherapy influence on the mentioned markers with regard to changes in the morphological appearance of the primary
tumor and its
metastases. Immunohistochemical examinations of Ki-67, Bcl-2 and Bak expression were conducted on sections collected from 135 patients treated surgically on invasive ductal
breast cancer. Sixty-four of these patients were administered preoperative
chemotherapy, whilst on 71 patients the surgery was performed without initial
chemotherapy. In the group of patients without preoperative
chemotherapy positive correlation in Ki-67 and Bcl-2 expression between primary
tumors and
lymph node metastases (p<0.0001, r=0.707; p<0.0001, r=0.604, respectively) was observed. In the group of patients after
chemotherapy positive correlation between primary
tumors and
lymph node metastases in case of Bcl-2 and Bak
proteins (p<0.04, r=0.424; p<0.02, r=0.478, respectively) was observed. It was also found that preoperative
chemotherapy has an influence on the expression of
proteins connected with proliferation and apoptosis and thus, it can influence neoplastic process biology. It does not have any significant impact on the proapoptotic
Bak protein expression either in primary
tumor or in
lymph node metastases of
breast cancer. However, it is related to lower expression of antiapoptotic Bcl-2
protein (p<0.0005) and of Ki-67 proliferation marker (p<0.03) in primary
tumors, which indirectly indicates a beneficial influence of preoperative
chemotherapy on the primary
tumor. Concurrently, the influence of
neoadjuvant therapy on
lymph node metastases seems to be relatively small, which can limit its effectiveness.