STAT3 and neoplasm: Specifically, the expression of the tumor suppressor genes Pten and Pdcd4, which are negative regulators of the pro-tumorigenic signaling pathways engaged by the Gp130 receptor pathway, was attenuated in adenomas after the Dox-induced expression of a luciferase control hairpin in Gp130F/F;shLuc;rtTA mice, as opposed to mice expressing a Stat3 hairpin which displayed the significant expression of both Pten and Pdcd4 (Figure 5A).