Johnson et al. (2010) demonstrated that treatment of MCF7 breast cancer cells with 20–40 μM carnosol for 48 h led to decreased androgen receptor (AR) and estrogen receptor (ER-α) mRNA and protein levels, as well as a dose-dependent decrease in cell viability with a half maximal inhibitory concentration (IC50) value of 25.6 μM (Table 3) [44]. Here, ESR1 is linked to breast cancer.