Considering receptor interactions, ERα molecular partners are endowed with different functions (Nassa et al., 2019a) and comprise co-regulators (Ambrosino et al., 2010; Tarallo et al., 2011; Cirillo et al., 2013) and epigenetic modulators (Nassa et al., 2019b) that drive gene expression changes underlying BC development and progression. This evidence concerns the gene ESR1 and breast cancer.