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Down-regulation of PHLDA1 gene expression is associated with breast cancer progression

Maria Aparecida Nagai1, José Humberto T G Fregnani, Mário Mourão Netto

  • 1Disciplina de Oncologia, Departamento de Radiologia, Faculdade de Medicina, Universidade de São Paulo, CEP 01246-903, São Paulo, Brazil. nagai@usp.br

Breast Cancer Research and Treatment
|January 11, 2007
PubMed

Insights

Reduced expression of PHLDA1 (pleckstrin homology-like domain, family A, member 1) in breast tumors indicates a poorer prognosis. This finding suggests PHLDA1 could be a valuable prognostic marker for breast cancer patients.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Previous studies indicated down-regulation of PHLDA1 mRNA in breast tumors.
  • PHLDA1, also known as TDAG51, is a gene implicated in cellular processes.

Purpose of the Study:

  • To investigate the expression pattern of PHLDA1 in breast cancer.
  • To determine the prognostic value of PHLDA1 in breast cancer patients.

Main Methods:

  • Quantitative Real Time PCR (qPCR) for PHLDA1 mRNA expression in 74 tumors.
  • Immunohistochemistry (IHC) using Tissue Microarrays (TMA) for PHLDA1 protein expression in 699 tumors.
  • Analysis of disease-free and overall survival in relation to PHLDA1 expression.

Main Results:

  • Reduced PHLDA1 mRNA expression was observed in 72% of primary breast tumors.
  • Negative PHLDA1 protein expression was found in 73% of analyzed cases.
  • Down-regulation of PHLDA1 protein was a significant predictor of poor prognosis, correlating with shorter disease-free and overall survival (P < 0.001).
  • Reduced PHLDA1 expression, particularly with low Estrogen Receptor (ER) levels, indicated the worst outcomes (P < 0.001).
  • Multivariate analysis confirmed PHLDA1 protein expression as an independent prognostic factor.

Conclusions:

  • PHLDA1 expression is significantly reduced in breast tumors.
  • PHLDA1 protein down-regulation is a strong and independent prognostic marker for poor survival in breast cancer patients.
  • PHLDA1 represents a potential biomarker for predicting breast cancer outcomes.

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