Desnoyers and colleagues performed a network meta-analysis to majorly investigate the safety of different CDK4/6 inhibitors in metastatic BC [23] and suggested no statistical difference in comparison of ribociclib versus palbociclib and comparison of abemaciclib versus palbociclib regarding PFS and OS after differentiating endocrine therapies to be AI and fulvestrant, which were consistent with our findings. This evidence concerns the gene CDK4 and breast cancer.