To date, three commercially available signatures (Prosigna, Endopredict, Breast Cancer Index) are recommended by several guidelines as prognostic tools in HR_positive, HER2-negative breast cancer with up to 3 positive nodes, including the NCCN algorithm with a level of evidence 2A [94], the ASCO guidelines (moderate strength) [95] and the ESMO guidelines (1B) [96], and AGO guidelines (AGO+) [98]. This evidence concerns the gene ERBB2 and breast cancer.