PIK3CA and cancer: Furthermore, different cancer hallmarks were associated with CCND1 amplification, including G2M checkpoints, p53 pathway, epithelial–mesenchymal transition, (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling, KRAS signaling, transforming growth factor (TGF)-b signaling, phosphoinositide 3-kinase, and hypoxia signaling in the pan cancer cohort of the TCGA.