ESR1 and breast cancer: ERα has been identified as a viable drug target in resistant BC and thus the development of SERD therapies that specifically target the elimination of ERα is of considerable interest all the more so as fulvestrant, the only SERD currently approved by the FDA, suffers from poor oral bioavailability and has to be administered intramuscularly (Nathan et al., 2017; Shagufta et al., 2020; Downton et al., 2022; Farkas et al., 2022).