ESR1 and breast cancer: Kim et al. recently reported that expression of YAP, CTGF, and CYR61 is elevated in recurrent breast cancer tissues after tamoxifen treatment; they also showed that YAP overexpression leads to tamoxifen-resistance and downregulation of ERα (Kim et al., 2021), as is consonant with the notion that expression of ERα is decreased in TNBC cell lines.