Furthermore, we found Bmi1 was inversely related with cytochrome-C release and casepase9 and caspase7 activation after 100mg/L 5-Fu treatment on selected cell lines for 24h (Figure 2C and D), suggesting Bmi1 affect the mitochondrial apoptotic pathway induced by 5-Fu in breast cancer cells. Here, CYCS is linked to breast carcinoma.