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Updated: Feb 13, 2026
Studying the Role of Alveolar Macrophages in Breast Cancer Metastasis
Published on: June 26, 2016
The Complex Subtype-Dependent Role of Connexin 43 (GJA1) in Breast Cancer
Mélanie Busby1, Michael T Hallett2, Isabelle Plante3
1INRS-Institut Armand-Frappier, Laval, QC H7V 1B7, Canada. melanie.busby@inrs.iaf.ca.
Abstract:
Gap junction transmembrane channels allow the transfer of small molecules between the cytoplasm of adjacent cells. They are formed by proteins named connexins (Cxs) that have long been considered as a tumor suppressor. This widespread view has been challenged by recent studies suggesting that the role of Connexin 43 (Cx43) in cancer is tissue- and stage-specific and can even promote tumor progression. High throughput profiling of invasive breast cancer has allowed for the construction of subtyping schemes that partition patients into at least four distinct intrinsic subtypes. This study characterizes Cx43 expression during cancer progression with each of the tumor subtypes using a compendium of publicly available gene expression data. In particular, we show that Cx43 expression depends greatly on intrinsic subtype. Tumor grade also co-varies with patient subtype, resulting in Cx43 co-expression with grade in a subtype-dependent manner. Better survival was associated with a high expression of Cx43 in unstratified and luminal tumors but with a low expression in Her2e subtype. A better understanding of Cx43 regulation in a subtype-dependent manner is needed to clarify the context in which Cx43 is associated with tumor suppression or cancer progression.
Insights
Connexin 43 (Cx43) expression varies by breast cancer subtype, influencing patient survival. Understanding this subtype-specific role is crucial for clarifying Cx43
Area of Science:
- Oncology
- Molecular Biology
- Genomics
Background:
- Gap junctions, formed by connexins (Cxs), facilitate intercellular communication.
- Connexin 43 (Cx43) was traditionally viewed as a tumor suppressor.
- Emerging evidence suggests Cx43's role in cancer is context-dependent, potentially promoting tumor progression.
Purpose of the Study:
- To investigate Cx43 expression patterns across different invasive breast cancer subtypes.
- To correlate Cx43 expression with tumor grade and patient survival within each subtype.
Main Methods:
- Analysis of publicly available gene expression datasets for invasive breast cancer.
- Characterization of Cx43 expression in relation to intrinsic tumor subtypes and tumor grade.
Main Results:
- Cx43 expression significantly differs across intrinsic breast cancer subtypes.
- Cx43 co-expression with tumor grade is subtype-dependent.
- High Cx43 expression correlated with better survival in unstratified and luminal tumors, but low expression correlated with better survival in the Her2 subtype.
Conclusions:
- Cx43's role in breast cancer is highly subtype-specific.
- Subtype-dependent regulation of Cx43 is critical for understanding its dual role in tumor suppression and progression.
- Further research into Cx43's context-specific functions is needed for therapeutic implications.
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