ERBB2 and breast cancer: In particular, the aforementioned multigene assays (Mammaprint, OncotypeDX, PAM50 and Endopredict) provide prognostic and in part predictive information in a subset of breast cancer patients with early disease (hormone receptor positive, HER2-negative tumors, up to 5 cm in maximal diameter, with up to three positive lymph nodes), while no such robust evidence-based information is available for more advanced breast cancer stages, neither with transcriptomic nor with proteomic approaches.