Gallen Consensus Conference,24,36 the Ki-67 proliferation marker,37 rather than grading, was taken into consideration for the separation of HR-positive/HER-2-negative tumors in luminal A and luminal B subtypes, two groups with different prognosis.38 This recommendation was based on data suggesting that Ki-67 levels >14 % were able to identify a high-risk group in terms of prognosis.39,40 In the absence of Ki-67 determination, grading is still used to differentiate luminal molecular subtypes.8 The prognostic role of Ki-67 in breast cancer is controversial. This evidence concerns the gene ERBB2 and breast cancer.