Recently, treatment combining CTx‐648 has been shown to demonstrate robust efficacy in various ET‐resistant ER+/HER2− breast cancer cell models, involving doxycycline‐inducible HA‐ESR1 Y537S models, NF1‐deficient models, and FOXA1 F266L and SY242CS mutants in T47D and MCF7 cells [132]. Here, ESR1 is linked to breast cancer.