[Research advances on alpha-fetoprotein physiological function and clinical potential].

Alpha-fetoprotein (AFP), a tumor-associated fetal protein, has been employed as a serum fetal defect/tumor marker to monitor disease progression. Besides this, AFP has many important physiological functions. As a tool of binding and transporting ligands, AFP may bind and transport fatty acids, steroids, heavy metal ions, drugs and some environmental contaminants. As a growth regulator, AFP is capable of both enhancement and inhibition. This function is dose-dependent. The regulatory mechanisms might involve apoptotic regulation, cytoplasmic signaling modulation, and receptor desensitization. As an anticancer drugs-ligand carrier, AFP can transport drugs into target tumor cells by binding AFP receptors overexpressed in the surface of tumor cells, and thus increase antitumor efficiency. In addition, AFP can be employed to chemoprevent breast cancer and possibly other tumors on the basis of its growth suppressive properties.