ESR1 and neoplasm: Other emerging therapeutic platforms, such as ER proteolysis-targeting chimeras (ER-PROTACs) like ARV-471 and ERD-3111 (63–66), complete estrogen receptor antagonists (CERANs) such as OP-1250 (Palazestrant) (67), and selective estrogen receptor covalent antagonists (SERCAs) like H3B-6545 (68), have demonstrated compelling preclinical anti-tumor efficacy and significant potency against clinically relevant ERα mutants, including Y537S and D538G.