Gallen Consensus Meeting suggested that the Ki67 LI was important for distinguishing between ‘‘luminal A” and ‘‘luminal B (HER2-negative)” breast cancer subtypes and advised adjuvant chemotherapy for luminal B but not for luminal A. Therefore, the standardization of the assessment of Ki67 LI is considered more important because of its impaction on clinical practice. This evidence concerns the gene ERBB2 and breast cancer.