Low risk scores given by OncotypeDX, Mammaprint, Endopredict, PAM50/Prosigna, or Breast Cancer Index (BCI) can be used regardless of the tumor size, to downstage hormone receptor-positive, HER2 negative and lymph node-negative tumors, placing them into the same prognostic category as T1a-T1b N0 M0 carcinomas. Here, ERBB2 is linked to breast cancer.