ESR1 and breast cancer: Although OncotypeDX (ODX)—a 21-gene molecular screening assay—is widely used in clinical practice to predict the distant recurrence and benefits from adjuvant chemotherapy for patients with breast cancer, its utility is limited as the ODX recurrence score is not consistent across all ages and relevant only in women with estrogen receptor (ER)-positive breast cancer, which limits its scope [25,26,27].