NR4A1 and breast cancer: Triple-negative breast cancer is the most aggressive molecular subtype of breast cancer.1 In contrast with mammary cancers of other subtypes (hormone receptor-positive HR+/HER2−, and HER2+), TNBCs do not express hormone receptors nor the HER2 oncogene, and thus are not candidates for hormone and anti-HER2 therapy.1 Chemotherapy is the only systemic therapy currently approved for this subtype.