ESR1 and breast cancer: A significant increase in risk of estrogen receptor-positive (ER+) and/or estrogen receptor- and progesterone receptor-positive (ER+/PR+) breast cancer due to alcohol intake has been reported, but no increase in risk of estrogen receptor-negative (ER-) and/or estrogen receptor- and progesterone receptor-negative (ER-/PR-) breast cancer [3–5, 20–23].