CDK4 and breast cancer: These results indicated that WXJ-202, after acting on breast cancer cells, could exert anti-tumor effects by inhibiting the expression of CDK4 and CDK6, thus affecting the formation of CDK4/6-Cyclin D1 complex and inhibiting the phosphorylation of Rb. In addition, the results also showed an increase in the apoptosis-related protein Caspase-3 and a decrease in the expression level of Pro-caspase-3.