MKI67 and breast cancer: The results showed that dual inhibition of H3K9me2 and H3K27me3 had a stronger pro-senescence effect than inhibition of either enzyme alone in breast cancer cells (MDA-MB-231), as indicated by the downregulation of CyclinA2 (Figure 2B,C), increased activity of SA-β-gal (Figure 2D,E), and a decrease in Ki67-positive cells (Figure 2F,G).