KI67 labeling ranged from 2 to 80%, and was significantly higher (p < 0.001) in HER2-positive (IHC3+ or IHC2+ and ISH+) than in HER2-negative (IHC0) and HER2-low (IHC1+ or IHC2+, ISH−) BC, with mean values of 34.2 (SD = 19.2), 15.8 (SD = 13.4) and 13.5 (SD = 6.5), respectively (Figure 2A). This evidence concerns the gene MKI67 and breast cancer.