Epidermal growth factor receptor (EGFR) polymorphisms and breast cancer among Hispanic and non-Hispanic white women: The Breast Cancer Health Disparities Study

The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases, functions in cellular processes essential to the development of cancer. Overexpression of EGFR in primary breast tumors has been linked with poor prognosis. We investigated the associations between 34 EGFR tagging SNPs and breast cancer risk and breast cancer-specific mortality in 4,703 Hispanic and 3,030 non-Hispanic white women from the Breast Cancer Health Disparities Study. We evaluated associations with risk of breast cancer defined by estrogen/progesterone receptor (ER/PR) tumor phenotype. Only one association remained statistically significant after adjusting for multiple comparisons. Rs2075112_GA/AA was associated with reduced risk for ER-/PR+ tumor phenotype (odds ratio (OR), 0.34; 95% confidence interval (CI) 0.18-0.63, p adj=0.01). All additional results were significant prior to adjustment for multiple comparisons. Two of the EGFR polymorphisms were associated with breast cancer risk in the overall study population (rs11770531_TT: OR, 0.56, 95% CI 0.37-0.84; and rs2293348_AA: OR, 1.20, 95% CI 1.04-1.38) and two polymorphisms were associated with risk among Hispanics: rs6954351_AA: OR, 2.50, 95% CI 1.32-4.76; and rs845558_GA/AA: OR, 1.15, 95% CI 1.01-1.30. With regard to breast cancer-specific mortality, we found positive associations with rs6978771_TT hazard ratio (HR), 1.68; 95% CI 1.11-2.56; rs9642391_CC HR, 1.64; 95% CI 1.04-2.58; rs4947979_AG/GG HR, 1.36; 95% CI 1.03-1.79; and rs845552_GG HR, 1.62; 95% CI 1.05-2.49. Our findings provide additional insight for the role of EGFR in breast cancer development and prognosis. Further research is needed to elucidate EGFR's contribution to ethnic disparities in breast cancer.