Skip to main content
  • Oral Presentation
  • Published:

Molecular distinctions among ERBB2-overexpressing breast cancers

HER2 or c-ERBB2/neu is a member of the epidermal growth factor receptor (EGFR) family and encodes a tyrosine kinase receptor. Overexpression of HER2 protein is generally attributable to gene amplification. HER2 is overexpressed in 20–30% of primary invasive breast carcinomas and in a greater proportion of in situ breast cancers. Invasive breast cancers that overexpress HER2 are generally higher stage, show lymph node positivity, and have higher S-phase. Moreover, they are often associated with poor prognosis, particularly in node-positive patients.

Microarray studies have subdivided breast cancers into several subtypes. HER2-overexpressing ER-negative tumors are generally classified within a single subtype denoted ERBB2-overexpressing. However, ER-positive HER2-overexpressing tumors are usually intermixed with other ER-positive tumors that do not show HER2 overexpression.

Our recent population-based study evaluating HER2 overexpression and hormone receptor status has unexpectedly found that the majority of HER2-overexpressing tumors are hormone receptor-positive and are more common than HER2-overexpressing ER-negative breast cancers. This implies that the ERBB2-overexpressing molecular subtype, which is associated with ER-negative status, only includes a minority of HER2-overexpressing tumors. We therefore studied gene expression patterns of HER2-overexpressing breast cancers and found several tumor subtypes with distinctive molecular signatures. These ERBB2-overexpressing subtypes spanned the range of hormone receptor status and highlighted different biological characteristics. Since the clinical course varies among patients with HER2-positive tumors, as does their response to targeted therapy, differences in global gene expression among HER2-overexpressing tumors could be important in distinguishing patients for the design and delivery of individualized targeted therapies.

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Jeffrey, S. Molecular distinctions among ERBB2-overexpressing breast cancers. Breast Cancer Res 7 (Suppl 2), S.22 (2005). https://0-doi-org.brum.beds.ac.uk/10.1186/bcr1065

Download citation

  • Published:

  • DOI: https://0-doi-org.brum.beds.ac.uk/10.1186/bcr1065

Keywords