We screened the expression of ERβ2 in a panel of ten breast cancer cell lines, including four ER-positive luminal (MCF-7, MDA-MB-175, ZR-751, CAMA-1), two HER2-positive (SK-BR-3 and HCC1569) and four TNBC (Hs578T, MDA-MB-231, BT549 and BT20) cell lines. Here, ESR1 is linked to breast cancer.