STAT3 and gastric cancer: Although we can not preclude the likely involvement of other growth factors and/or cytokines, the studies of neutralizing IL-17a or the inhibition of JAK2/STAT3 pathway activation with AG490 reveal that IL-17a is an important mediator of the tumor-promoting effects of TANs, which promote EMT via the activation of the JAK2/STAT3 signalling pathway in GC.