ESR1 and breast cancer: Furthermore, the isomeric precursor of liquiritigenin, isoliquiritigenin (Ramalingam et al., 2018) and an extract from licorice root, which also consists of liquiritigenin, had been shown to downregulate ERα protein levels in MCF7 cells (Maggiolini et al., 2002; Hu et al., 2009), while liquiritigenin itself, as found in the current study, significantly downregulated ERα and upregulated ERβ levels in a BT-474 breast cancer cell-derived tumor xenograft model (Liang et al., 2022).