This limitation of anatomic staging has resulted in the incorporation of ER status, HER2 status, grade, and molecular tumor characteristics into the 8th edition revision of AJCC cancer staging for breast cancer.25, 26 Unfortunately, the survival difference between the two T2 subcategories in this study was not fully explained by the model after adjusted for those biologic risk factors (Tables 2 and 3). This evidence concerns the gene ESR1 and breast cancer.