ESR1 and breast cancer: However, a recent ChIP-seq study demonstrated that treatment of MCF-7 breast cancer cells with the AR antagonists enzalutamide or MJC13 (which directly binds to the ligand-binding domain of AR with higher affinity than dihydrotestosterone) decreased the number of ER genomic binding sites by almost 50%, implicating a role for AR in ER genomic binding in response to 17β-estradiol (E2) [21].