A population‐based, case–control study of 1021 women, ages 20 to 44 years, with BC (779 ER+, 182 triple negative BC −TNBC, and 60 ER−/human epidermal growth factor receptor 2‐HER2‐overexpressing) demonstrated a slight positive association of increase in BMI since age 18 years, with an increased risk of TNBC [49]. This evidence concerns the gene ERBB2 and breast cancer.