Many studies have demonstrated that high Ki67 expression (with a cut-off value of 30% for the percentage of Ki67-expressing cells) is associated with poor prognosis and can predict anti-tumor therapy efficacy in breast cancer (Kurebayashi et al. 2014; Shao et al. 2021; Zhu et al. 2020). This evidence concerns the gene MKI67 and breast carcinoma.