MAPK3 and gastric cancer: Nonetheless the decreased activation of JAK2 and STAT3 is in keeping with the established role of these cytokine/growth factor signalling components in gastric cancer progression [5], [27] and demonstrates that in vivo, and when isolated from the effects of H.pylori infection, it is predominantly altered activation of STAT3, and not ERK1/2 that is crucial for tumour development.