PIK3CA and esophageal cancer: Although overexpression of PTEN (phosphatase and tensin homolog), which acts as a lipid phosphatase to dephosphorylates PIP3 and therefore negatively regulates PI3K/AKT pathway, was found to suppress esophageal cancer cell growth [22], experimental data on direct targeting of PI3K/AKT in the preclinical setting are limited.