RES can inhibit activating enzymes such as CYP19 (aromatase) and CYP1B1 (a kind of cytochrome P450 enzyme), and induce the expression of detoxification enzyme of NQO1 (NAD(P)H:quinone oxidoreductase 1), thus blocking the formation of estrogen-DNA adducts to protect against estrogen-initiated cancer (Figure 3). The gene discussed is CYP19A1; the disease is cancer.