AR was also a significant prognostic factor in subgroups with a tumor size of >2 cm, stage II cancer, a positive ER, a negative PR, a negative HER2, a histologic grade 1 or 2, a positive lymphovascular invasion, age ≤50 years, a body mass index ≤25 kg/m2, no radiation therapy, chemotherapy, no anti-HER2 therapy, and endocrine therapy. This evidence concerns the gene ESR1 and cancer.