The PI3K-AKT-mTOR pathway proteins and the CDK-Rb-E2F pathway proteins are widely co-expressed in different tumor types, and the two pathways are the relationship between the upstream and downstream, signifying that the combined targeting inhibition of CDK4/6 and PI3K-AKT-mTOR should further improve the efficacy [59]. Here, PIK3CA is linked to neoplasm.