JAK2 and gastric cancer: Furthermore, Upd induction enhanced the 4XCG34394-luciferase reporter activity in a STAT92E-dependent manner, suggesting that CG34394 is a bona-fide STAT92E downstream target in Drosophila. To examine if this transcriptional regulation is evolutionarily conserved in mammals, we tested the expression of GRAMD1B in gastric cancer cell lines, and found that its levels are induced by IL-6 stimulation but suppressed by the JAK2 inhibitor AG490.