ERBB2 and cancer: In this regard, validation data of three extensive randomized prospective studies to select ER+/HER2- patients who could benefit from adjuvant chemotherapy plus endocrine therapy are available: two of them (TAILORx, RxPONDER) used Oncotype DX (21 relevant genes by qRT-PCR) which classified ER+ cancers in three groups based on “recurrence scores” [23,24]; the third study (MINDACT) used MammaPrint (70 genes by microarray) to define BCs with high and low recurrence risk [25,26].