By comparing the expression of mCherry reporters we were able to reveal in vivo signaling pathways elicited after oncogenic KRAS constitutive activation in both pancreas and cerebellum, showing in vivo how TGFβ, Notch and Shh are involved in pancreatic adenocarcinoma and during MDB carcinogenesis. The gene discussed is KRAS; the disease is pancreatic adenocarcinoma.