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Apoptosis is a process associated with development and progression of breast cancer. The association between connexins and programmed cell death has only been demonstrated in a few studies. The aim of the present study was the evaluation of Cx26 and Cx43 expression in breast cancer in correlation with Bcl-2 and Bak proteins as well as with selected clinicopathological features. Tissue samples from 71 women were examined by immunohistochemistry, using the streptavidin-biotin-peroxidase complex technique for Cx26, Cx43, Bak and Bcl-2. Cytoplasmic expression of Cx26 and Cx43 was detected in 34 (47.9%) and 61 (85.9%) of breast cancers, respectively. Bcl-2 and Bak expression was found in 59 (83%) and 50 (70%) of studied cases, respectively. We found a positive correlation between Cx26 and Bak expression (r=0.541, p

Disturbance in expression of estrogen receptors together with changing influence of growth factor receptors and apoptosis associated proteins plays a role in breast cancer development and progression. However, immunohistochemical detection and relationships among these proteins were not often considered in relation to breast cancer and a few evaluations of expression provided mismatching results and conclusions. Consequently, we examined by immunohistochemistry the expression of the insulin-like growth factor-I receptor (IGF-IR), estrogen receptor alpha (ERalpha) and apoptosis-associated proteins, Bcl-2 and Bax, in human primary breast cancer, as well as analyzing the relationships among these proteins. The positive immunostaining for IGF-IR, ERalpha, Bcl-2 and Bax was noted in 56, 63.8, 82.8 and 50% of tumors, respectively. We observed that IGF-IR negatively correlated with ERalpha in the group of all tumors and in axillary node negative cancer (p0.03, p0.05, respectively), but not in the subgroup of node positive cancer. Expression of ERalpha correlated positively with Bcl-2 and negatively with Bax proteins (p0.0001, p0.05, respectively). We did not note significant relationships between IGF-IR and Bcl-2, or IGF-IR and Bax proteins. We found that increased Bax expression was associated with positive lymph node status, pT2 stage and G3 grade of tumors. Knowledge about alterations in the IGF-IR expression and relations of the receptor to other biological factors could help in our understanding of breast cancer biology and the importance of the IGF-IR in cancer progression as well as in effective management of breast cancer.

Breast cancer is often relatively slow growing, but at diagnosis about 40% of patients have regional spread to at least one axillary node. It has been shown that unrelated clones are in primary breast carcinomas. There is possibility that only a small subpopulation of the cells of the primary tumour (PT) metastasis. It has been shown that Ki-67 protein is a useful marker in histopathology, which is present during all active phases of the cell cycle and making possibility to assess growth fraction of tumour cells. The purpose of the study was to evaluate the expression of Ki-67 and comparison between the PTs and MRLNs as well as to estimate the relationships between Ki-67 and the chosen anatomoclinical features of the breast cancer. Immunohistochemical analyses for Ki-67 were performed on the PTs (69 cases without primary chemotherapy) and MRLNs (33 cases) of breast cancer. Increased expression of Ki-67 in PTs significantly correlated with pT2 stage of tumours (p0.05) and grade G3 (p0.04), but there was not relationship with lymph node status. Expression of Ki-67 positively correlated between PTs and MRLNs (p0.001). Comparison between PTs and matching MRLNs revealed that 23 (69.7%) cases showed a convergence between PTs and matching MRLNs with regard to negative or positive staining. We would like to emphasize the importance of studies concerning the proteins involved in proliferation in MRLNs, because knowledge about heterogeneity between PTs and MRLNs could shed light on tumour biology and may lead to development of more effective anti-cancer therapies.

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

The aim of the study was the evaluation of ERalpha and ERbeta expression in primary tumors and lymph node metastases of breast cancer as well as the assessment of the influence of preoperative chemotherapy on these receptors with regard to changes in morphological appearance of primary tumors and their metastases. Immunohistochemical examinations were conducted on surgically removed ductal invasive breast cancers and their lymph node metastases of 135 patients. Seventy-one patients were spared preoperative chemotherapy which was administered to other 64 patients. Primary breast cancers with preoperative chemotherapy showed lower mean percentage of cells with a positive reaction to ERalpha and ERbeta as compared to primary tumors without preoperative chemotherapy. There were positive correlations among primary tumors and lymph node metastases regardless of preoperative chemotherapy applied. On the other hand, ERalpha and ERbeta expressions were negatively correlated in primary tumors without chemotherapy in contrast to primary tumors after chemotherapy. Furthermore, it was observed that preoperative chemotherapy was responsible for significantly less damage to lymph node metastases of breast cancer in comparison to primary tumors. In cases of such advanced damage of primary tumors that made determination of estrogen receptor expression impossible, their evaluation was performed on metastases to regional lymph nodes. Although preoperative chemotherapy did not severely impair estrogen receptor expression, presented changes of their distribution are a sufficient reason for simultaneous labeling of estrogen receptors in both primary tumors and metastases due to various sensitivity to chemotherapy of primary cancers in comparison with involved lymph nodes.