With the advent of the era of big data and precision medicine, a variety of multigene prognostic tools, including Oncotype Dx and MammaPrint, have been established to predict outcomes and aid in adjunct therapy decision-making in patients with ER-positive, HER2-negative BC that are either lymph-node-negative or node-positive (one to three metastatic nodes) [17,18]. Here, ERBB2 is linked to breast cancer.