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. This evidence concerns the gene MTOR and breast carcinoma.