In 2017, the Early Breast Cancer Trials Collaborative Group (EBCTCG) showed in a review of more than 91 studies, which included a total of 46,000 patients, that more than 50% of the breast cancer recurrences in hormone receptor-positive breast cancer patients occur after completion of a 5-year period of endocrine therapy [11]. This evidence concerns the gene NR4A1 and breast cancer.