A phase III clinical trial BOLERO-2 (Study Details Everolimus in Combination With Exemestane in the Treatment of Postmenopausal Women With Estrogen Receptor Positive Locally Advanced or Metastatic Breast Cancer Who Are Refractory to Letrozole or Anastrozole ClinicalTrials.gov, 2023) assessed the effectiveness and survival rate of the mTORC1 inhibitor everolimus and the aromatase inhibitor exemestane in treating HR+/HER2-advanced breast cancer, leading to the approval of this combination. The gene discussed is ESR1; the disease is breast cancer.