In HER2-nonamplified BC with low Ki-67 index, no significant survival difference of OS (92% vs. 91%, p=0.90Figure 4(a)) and RFS (91% vs. 91%, p=0.76, Figure 4(b)) could be observed in HER2-low-positive BC and HER2-0 BC. This evidence concerns the gene MKI67 and breast cancer.