ESR1 and breast cancer: Among them, many regulatory associations have been revealed; for instance, miR-22 was demonstrated to inhibit ESR1 expression in breast cancer (Vesuna et al., 2021), whereas H19 could act as a sponge of miR-22 in many cell types (Gan, Lv & Liao, 2019; Sun, Mao & Ji, 2021).