Three types of human breast cells were treated with ethanol for 6 h: (a) the preneoplastic mammary epithelial cell line MCF10A, (b) the estrogen receptor‐negative epithelial derived breast cancer cell line MDA‐MB‐231, and (c) the estrogen receptor‐positive epithelial derived breast cancer cell line MCF7. Here, ESR1 is linked to breast cancer.