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

BMC Cancer. 2006 Jul 13;6:187. doi: 10.1186/1471-2407-6-187.


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.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cyclin-Dependent Kinase Inhibitor p27 / metabolism*
  • Disease-Free Survival
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Immunohistochemistry
  • Ki-67 Antigen / metabolism*
  • Lymphatic Metastasis / pathology
  • Middle Aged
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Receptor, ErbB-2 / metabolism
  • Tumor Suppressor Protein p53 / metabolism*


  • Ki-67 Antigen
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • Cyclin-Dependent Kinase Inhibitor p27
  • Receptor, ErbB-2