Nevertheless, the effect of Ras/Raf activation on STAT3 was consistent in these two tumor types in that, in both MTC and PTC, Ras/Raf activates STAT3 via the IL-6 family cytokine-mediated gp130/JAK pathway and STAT3 operates in the context of tumor suppression. Here, STAT3 is linked to medullary thyroid gland carcinoma.