Notably, the recent prospective phase 3 trial, WSG-ADAPT in HR + /HER2-negative disease suggests that Ki-67 as a dynamic biomarker after short-term neoadjuvant ET in combination with the RS result might be an additional biomarker to guide adjuvant systemic therapy decisions in pN0-1 HR + HER2-negative breast cancer. The gene discussed is ERBB2; the disease is breast cancer.