PTEN is a tumor suppressor protein with both protein tyrosine phosphatase and lipid phosphatase activities. It mainly localizes to the cytoplasm and nucleus, where it negatively regulates cell survival, proliferation, and migration by dephosphorylating phosphatidylinositol-3,4,5-trisphosphate (PIP3), thereby acting on the PI3K/Akt signaling pathway. The gene expression of PTEN is tissue-specific, and its loss of function or downregulation is closely associated with the occurrence and development of various cancers, as well as some hereditary diseases such as Cowden syndrome. Precise regulation of PTEN is crucial for maintaining normal balance in cell growth and inhibiting tumor development.