1. Centre de recherche du CHU de Québec, Quebec City, QC, Canada; 2. Centre des maladies du sein Deschênes-Fabia, Saint-Sacrement Hospital, Quebec City, QC, Canada; 3. Faculté de médecine, Université Laval, Quebec City, QC, Canada
The human epidermal growth factor receptor-2 (HER2) overexpression occurs in about 15% of human breast cancers and is a marker of poor survival. However, it is unclear if common HER2 polymorphisms are associated with breast cancer prognostic factors. This study aimed to evaluate the association between HER2 polymorphisms and breast cancer prognostic factors in non-metastatic HER2-positive breast cancer patients. Among 73 women, HER2 polymorphisms (Ile655Val and Ala1170Pro) were assessed using TaqMan assays in normal and tumor breast tissues. In normal breast tissue, the variant allele 1170Pro was associated with younger age (P=0.007) and the presence of lymphovascular invasion (P=0.06). Similar associations were observed when this polymorphism was assessed in tumor breast tissue. No association was found between Ile655Val polymorphism and breast cancer prognostic factors. However, we observed a difference of Ile655Val or Ala1170Pro genotyping between normal and tumor breast tissues (P=0.03 and P=0.01, respectively). These preliminary results suggest that HER2 Ile655Val and Ala1170Pro polymorphisms may play a role in breast carcinogenesis, but only Ala1170Pro polymorphism is associated with breast cancer prognostic factors in non-metastatic HER2-positive breast cancer patients.