NR4A1 and breast cancer: This latter finding resembles the clinical behavior of HER2-positive breast cancer, as confirmed by a recent study of the Unicancer Epidemiological Strategy and Medical Economics (ESME) metastatic breast cancer (MBC) database (n = 16,701): 24.6% of the patients developed brain metastasis, and the risk was higher for patients with HER2-positive/hormone receptor (HR)- negative and triple-negative (TNBC) breast cancer (22).