ERBB2 and breast cancer: Exploratory analyses assuming dominance (GT/TT v GG) suggested elevated breast cancer risks for pre-menopausal (1.46, 0.99-2.15; p = 0.06), HER2 positive (1.48, 1.00-2.01; p = 0.05), and triple negative cases (2.01, 1.10-3.67; p = 0.02).