ESR1 and breast cancer: Isomangiferin is the major polyphenol (Table 1) quantified in the C. genistoides extract, P104 (5.094/100 g dry extract), and is 7.9 to 12.1-fold higher than the levels in the C. subternata Vogel extracts, SM6Met and CoT, respectively, and although no work has been done on its effect on ERα or ERβ protein levels it has been shown to inhibit MCF7 cell proliferation and to suppress tumor growth in a mouse breast cancer mouse xenograft model using MDA-MB-231 cells (Wang et al., 2018).