A multinational phase 3 randomized study (ClinicalTrials.gov identifier: NCT03778931, EMERALD) showed that monotherapy with elacestrant dramatically decreases the risk of cancer progression compared with SOC endocrine therapy in patients with ER+ and HER2− metastatic breast cancer (with or without ESR1 mutations) who had progression after first- or second-line treatment with the combination of endocrine therapy and a CDK4/6 inhibitor [58]. The gene discussed is ESR1; the disease is cancer.