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Downregulation of TSLC1 and DAL-1 expression occurs frequently in breast cancer

Gerwin Heller1, Joseph Geradts, Barbara Ziegler

  • 1Clinical Division of Oncology, Department of Medicine I, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.

Breast Cancer Research and Treatment
|January 30, 2007
PubMed

Insights

Tumor suppressor genes TSLC1 and DAL-1 are frequently inactivated by methylation in breast cancer, impacting cell adhesion and tumor progression. Methylation levels correlate with higher tumor grade and loss of hormone receptor expression.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • TSLC1 and DAL-1 are tumor suppressor genes crucial for cell adhesion.
  • Altered expression and methylation of these genes are implicated in various cancers.

Purpose of the Study:

  • To investigate the expression and methylation patterns of TSLC1 and DAL-1 in breast cancer.
  • To determine the correlation between gene inactivation and clinicopathological features of breast cancer.

Main Methods:

  • Analysis of TSLC1 and DAL-1 expression and methylation in breast cancer cell lines and primary tumors.
  • Treatment of breast cancer cells with demethylating agents (5-aza-2'-deoxycytidine and TSA) to assess gene re-expression.
  • Correlation analysis with tumor grade and hormone receptor status (ER, PgR).

Main Results:

  • Loss of TSLC1 and DAL-1 expression was frequent in breast cancer cell lines and primary tumors.
  • Methylation was observed in a significant proportion of breast cancer samples, correlating with gene silencing.
  • Demethylation treatment led to re-expression of TSLC1 and DAL-1.
  • TSLC1 and/or DAL-1 methylation was more frequent in high-grade (grade 3) tumors.
  • TSLC1 methylation correlated with the loss of Estrogen Receptor (ER) and Progesterone Receptor (PgR) staining.

Conclusions:

  • TSLC1 and DAL-1 are frequently inactivated by promoter methylation in breast cancer.
  • Gene methylation is a significant mechanism contributing to the loss of these tumor suppressors in breast cancer pathogenesis.
  • Methylation of TSLC1 and DAL-1 may serve as potential biomarkers for aggressive breast cancer subtypes.

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