The Onctoype DXTM Recurrence Score (ODXRS) is a 21-gene assay used to estimate the risk of distant recurrence and to evaluate the potential benefit of adjuvant chemotherapy for a specific subtype of breast cancer with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−), and lymph node-negative (LN−) early-stage invasive breast cancer [1,2,3]. This evidence concerns the gene ERBB2 and invasive breast carcinoma.