Thioredoxin (Trx) is a class of small redox proteins which is widely found in all organisms.It acts as antioxidant by facilitating the reduction of other proteins by cysteine thiol-disulfide exchange.Recently,thioredoxin is found to be over-expressed in many kinds of tumor,which is closely associated with tumor cell proliferation,apoptosis and cell cycle control.Trx is also found to promote the synthesis and stabilization of the HIF-1α protein.It is also related to the control of reactive oxygen species and chemoresistance of tumor cells.Trx has been proved to play an important role in promoting the metastasis of cancer,and may become a potential target for anti-metastasis of cancer.