Expression of Cyclin D1 and bcl-2 in Infiltrative Ductal Carcinoma of the Breast: Their Correlations and Clinical implications

Purpose: Cyclin D1 and bcl-2 are involved in cell proliferation and apoptosis in tumor development and are commonly expressed in breast cancer. But there are few clinical reports on the correlation between cyclin D1 and bcl-2 expression. This study was designed to analyze the correlations of cyclin D1 and bcl-2 and their clinical implications in breast cancer. Methods: Immunohistochemical expression of cyclin D1 and bcl-2 were studied in 342 infiltrative ductal carcinoma cases and were compared with clinicopathologic parameters such as age, tumor size, histologic grade, lymph node status, p53, c-erbB2 and hormone receptors. Results: Cyclin D1 expression was found in 86 of 342 cases (25.1%). Bcl-2 was positive in 227 of 342 cases (66.4%). Bcl-2 overexpression was associated with the high expression of cyclin D1 (p=0.001). Correlation was detected between both cyclin D1 and bcl-2 and hormone receptor positivity (p < 0.001). There was a reverse correlation between bcl-2 and histologic grade, p53, c-erbB2. And the bcl-2 overexpression group showed better disease free survival rates at 3-year follow up. Conclusion: Higher expression of cyclin D1 was associated with bcl-2 overexpression. Positive estrogen receptor expression was associated with high cyclin D1 and bcl-2 expression. Bcl-2 tends to correlate with a positive clinical outcome.