HER2 Codon 655 (Ile/Val) Polymorphism and Breast Cancer in Austrian Women

Abstract

Background: The overexpression of the human epidermal growth factor receptor 2 (HER2) in breast cancer (BC) is associated with impaired prognosis. Data concerning the HER2 codon 655 polymorphism (Ile/Val) and BC risk are conflicting.

Materials and methods: We studied the HER2 codon 655 (rs1136201) polymorphism in 80 Austrian patients with BC and 100 healthy volunteers by pyrosequencing and polymerase chain reaction. Associations between codon 655 allelic variants and clinicopathological variables (e.g. age, stage of disease, tumor type, grading, and receptor status) were studied with 2×2 tables.

Results: The genotypic distributions in patients with BC (AA: 63.75%, AG: 32.5%, GG: 3.75%) and controls (AA: 63%, AG: 34%, GG: 3.7%) were virtually identical (odds ratio=1.03, 95% confidence interval=0.56-1.90). A non-significant link between carrying at least one G allele and more aggressive tumor type (estrogen receptor-negative p=0.08, G3 tumor p=0.19) was observed.

Conclusion: Genotypic variation within the codon 655 of HER2 does not alter the BC risk in Caucasian Austrian women. The association between the G allele and more aggressive tumor types requires further investigation.

Keywords: ERBB2; HER2; Ile655Val; breast cancer; codon 655; polymorphism.