Constitutive Activation of STAT-3 and Neoplasm Invasion and Metastasis

The disorder of JAK-STAT(janus tyrosine kinase-signal transducer and activator of transcription) is one of the leading causes for the occurrence of tumors.Recent studies showed that STAT-3,an important transcription factor of JAK-STAT signal transduction pathway,can promote the rapid induction of genes by directly transducing signals from the receptor into the nucleus,and to play a pivotal role in mediating the biological response for this ligands.However,STAT-3 appears to have a dark side as well.STAT-3 can sus-tainablely activate in the tumor cells,and serve as a new target for tumor therapy as a protooncogene.Thus,it is helpful to gain a better understanding of the role of STAT-3 in tumorigenesis with the overview of the relationship between the constitutive activation of STAT-3 and the neoplasm invasion,metastasis,and cancer stem cells.