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Inactivation of PTEN is associated with a low p27Kip1 protein expression in breast carcinoma

Shinichi Tsutsui1, Hiroshi Inoue, Kazuhiro Yasuda

  • 1Department of Breast Surgery, Matsuyama Red Cross Hospital, Bunkyo, Matsuyama, Japan. tsutsui@lime.ocn.ne.jp

Cancer
|October 7, 2005
PubMed
Abstract

Insights

Reduced PTEN and p27 protein expression in breast cancer correlates with poor prognosis. This combined loss suggests an aggressive tumor phenotype and worse disease-free survival, highlighting their importance as prognostic factors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Research

Background:

  • PTEN protein expression is reduced in a significant portion of breast carcinomas.
  • The cell cycle inhibitor p27Kip1 (p27) is a downstream mediator of PTEN's role in cell cycle regulation.

Purpose of the Study:

  • To investigate the correlation between PTEN and p27 protein expression in invasive ductal breast carcinomas.
  • To determine the prognostic significance of combined PTEN and p27 protein expression on disease-free survival.

Main Methods:

  • Immunohistochemical evaluation of PTEN and p27 protein expression in 228 invasive ductal breast carcinomas.
  • Statistical analysis including univariate and multivariate analyses to assess correlations and prognostic factors.

Main Results:

  • Reduced PTEN expression was observed in 29% of cases, and low p27 expression in 43%.
  • A significant correlation was found between reduced PTEN and low p27 protein expression (P = 0.0214).
  • Combined decreased PTEN and p27 expression was significantly associated with worse disease-free survival (P = 0.0044).

Conclusions:

  • Reduced PTEN protein expression is significantly correlated with low p27 protein expression in breast carcinoma.
  • A combined loss of PTEN and p27 function is associated with an aggressive phenotype and poor prognosis in breast cancer patients.

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