RB1 and breast carcinoma: In patients, significant differences were not observed between mifepristone levels after 1 or 2 weeks of treatment (day 7 (mean ± s.d.): 300.3 ± 31.7 ng/mL (690 ± 72.9 nmol/L); day 14: 320 ± 54.3 ng/mL (745 ± 126.4 nmol/L; n = 11); (Elia et al. 2022)), and they were more than twenty times higher than those observed in the animal model using mifepristone pellets (P < 0.001),suggesting that the effect of lower mifepristone doses in breast cancer patients with higher levels of PRA than PRB should be tested.