We first assessed the association between BMI and BC-specific driver mutations using combined data from the METABRIC and ICGC cohorts for the NST ER+/HER2− and NST ER−/HER2− subgroups, and data from the ELBC cohort for the ILC ER+/HER2− subgroup (Fig. 1, Supplementary Figs. 2–4). This evidence concerns the gene ESR1 and breast cancer.