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Open Access Highly Accessed Research article

Bcl-2 protein expression is associated with p27 and p53 protein expressions and MIB-1 counts in breast cancer

Shinichi Tsutsui1*, Kazuhiro Yasuda2, Kosuke Suzuki2, Hideya Takeuchi2, Takashi Nishizaki3, Hidefumi Higashi2 and Shoichi Era4

Author Affiliations

1 Department of Breast Surgery, Matsuyama Red Cross Hospital, Matsuyama, Japan

2 Department of Surgery, Beppu Medical Center, Beppu, Japan

3 Department of Surgery, Matsuyama Red Cross Hospital, Matsuyama, Japan

4 Department of Pathology, Beppu Medical Center, Beppu, Japan

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BMC Cancer 2006, 6:187  doi:10.1186/1471-2407-6-187

Published: 13 July 2006

Abstract

Background

Recent experimental studies have shown that Bcl-2, which has been established as a key player in the control of apoptosis, plays a role in regulating the cell cycle and proliferation. The aim of this study was to investigate the relationship between Bcl-2 and p27 protein expression, p53 protein expression and the proliferation activity as defined by the MIB-1 counts. The prognostic implication of Bcl-2 protein expression in relation to p27 and p53 protein expressions and MIB-1 counts for breast cancer was also evaluated.

Methods

The immunohistochemical expression of Bcl-2 protein was evaluated in a series of 249 invasive ductal carcinomas of the breast, in which p27 and p53 protein expressions and MIB-1 counts had been determined previously.

Results

The Bcl-2 protein expression was found to be decreased in 105 (42%) cases. A decreased Bcl-2 protein expression was significantly correlated with a nuclear grade of III, a negative estrogen receptor, a decreased p27 protein expression, a positive p53 protein expression, positive MIB-1 counts and a positive HER2 protein expression. The incidence of a nuclear grade of III and positive MIB-1 counts increased as the number of abnormal findings of Bcl-2, p27 and p53 protein expressions increased. A univariate analysis indicated a decreased Bcl-2 protein expression to be significantly (p = 0.0089) associated with a worse disease free survival (DFS), while a multivariate analysis indicated the lymph node status and MIB-1 counts to be independently significant prognostic factors for the DFS.

Conclusion

The Bcl-2 protein expression has a close correlation with p27 and p53 protein expressions and the proliferation activity determined by MIB-1 counts in invasive ductal carcinoma of the breast. The prognostic value of Bcl-2 as well as p27 and p53 protein expressions was dependent on the proliferation activity in breast cancer.