For ER−&PR−&HER2+ cases, the heterozygous genotype (G/A) of rs13387042 significantly increased breast cancer risk under the codominant (adjusted OR = 1.68, 95% CI = 1.07–2.65, P = 0.03), dominant (adjusted OR = 1.64, 95% CI = 1.04–2.58, P = 0.04), and overdominant models (adjusted OR = 1.69, 95% CI = 1.07–2.67, P = 0.03) with an A-allelic trend of OR = 1.55 (95% CI = 1.00–2.40) after adjusting for potential cofounders (Table 4). Here, ERBB2 is linked to breast cancer.