MTOR and hepatocellular carcinoma: PIK3CA has been implicated in various cancers, including gastric cancer, hepatocellular cancer, non-small-cell lung cancer, and breast cancer and it can activate the PI3K/AKT/mTOR signaling pathway by enhancing the activity of PI3K lipid kinase, thus promoting the invasive and metastasizing ability of cancer cells and contributing to tumor development.