ERBB2 and breast cancer: Subset analysis only based on HER2 receptor indicated that the LIPG-breast cancer relationship was restricted to HER2-negative breast cancers (Multivariable OR for the highest LIPG category (95% CI) 4.39 (1.70–12.03), P-trend = 0.012, and 1.10 (0.28–4.32), P-trend = 0.745, for HER2-negative and HER2-positive tumors, respectively).