ESR1 and neoplasm: Anti-hormonal therapy options which include aromatase inhibitors (e.g., letrazole and anastrozole), progestins (megestrol acetate), selective estrogen receptor modulators (e.g., tamoxifen) and gonadotropin receptor antagonists may work by inhibition of proliferation of neoplastic cells directly through receptors on the tumour cells or indirectly by suppression of gonadotropins [28].