Eight of 29 BC cell lines were ER+, four of 29 cell lines were PR+, 11 of 29 showed strong expression of HER2 (indicated by ++ and +++), another 11 cell lines showed weak expression of HER2 (indicated by +), and eight of 29 cell lines were AR+ in the immunoblots (Table 3, Figure S1). Here, ESR1 is linked to breast cancer.