STAT3 and neoplasm: In another GEMM in which KRASG12D expression can be reversibly switched on/off by doxycycline treatment, maintenance of neoplastic epithelia, activation of fibroblasts, and infiltration of immune cells require the continual expression of KRASG12D, which upregulates different tumor-intrinsic signaling pathways including the sonic-Hedgehog and inflammatory IL-6/STAT3 pathways [34].