Studies have shown that cancer is regulated by a variety of signaling pathways such as MAPK/ERK [107–109], PI3K/Akt/mTOR [110–112], NF-κB [113], p53/p21 [114,115], Cyclin B1/Cdc2 [116–118] and other signaling networks to inhibit the activity in multiple targets, and depth explorations of the mechanisms of these pathways can better reveal the molecular basis of antitumor effects. Here, PIK3CA is linked to cancer.