ESR1 and breast cancer: The dominant perception is that ERβ1 promotes survival in ERα-negative BC (Nakopoulou et al., 2004; Rosin et al., 2014; Sun et al., 2018; Shalabi et al., 2021), although some studies have indicated that ERβ1 expression is not associated with outcomes of patients with TNBC (Heitz et al., 2019; Takano et al., 2023).