Connexins 26 and 43 correlate with Bak, but not with Bcl-2 protein in breast cancer

Oncol Rep. 2005 Aug;14(2):325-9.

Abstract

Apoptosis is a process associated with development and progression of breast cancer. The association between connexins and programmed cell death has only been demonstrated in a few studies. The aim of the present study was the evaluation of Cx26 and Cx43 expression in breast cancer in correlation with Bcl-2 and Bak proteins as well as with selected clinicopathological features. Tissue samples from 71 women were examined by immunohistochemistry, using the streptavidin-biotin-peroxidase complex technique for Cx26, Cx43, Bak and Bcl-2. Cytoplasmic expression of Cx26 and Cx43 was detected in 34 (47.9%) and 61 (85.9%) of breast cancers, respectively. Bcl-2 and Bak expression was found in 59 (83%) and 50 (70%) of studied cases, respectively. We found a positive correlation between Cx26 and Bak expression (r=0.541, p<0.0001) as well as between Cx43 and Bak (r=0.589, p<0.0001), but not between the studied connexins and Bcl-2. The expression of Cx26 was not associated with age, tumor size, lymph node status or histological grade. However, we observed an association between Cx43 expression and histological grade G3 (p<0.04). Cytoplasmic localization of evaluated connexins supports the concept of alterations in connexins expression in breast cancer cells. The associations of evaluated connexins with Bak protein could suggest that connexins localized in the cytoplasm may participate in signaling apoptotic pathways.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / analysis*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Connexin 26
  • Connexin 43 / analysis
  • Connexins / analysis
  • Female
  • Humans
  • Immunohistochemistry
  • Membrane Proteins / analysis
  • Middle Aged
  • Proto-Oncogene Proteins c-bcl-2 / analysis
  • bcl-2 Homologous Antagonist-Killer Protein

Substances

  • BAK1 protein, human
  • Biomarkers, Tumor
  • Connexin 43
  • Connexins
  • GJB2 protein, human
  • Membrane Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-2 Homologous Antagonist-Killer Protein
  • Connexin 26