Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Schematic model of intestinal tumourigenesis. (a) Aberrant activation of WNT and KRAS signalling drives intestinal tumour formation both from crypts (bottom-up model) and villi (top-down model). (b) High levels of transforming growth factor-β (TGFβ) signalling are present in the top-down model and this restrains tumourigenesis. (c) Loss of Tgfbr1 promotes intestinal tumourigenesis. (d) Top-down tumours lacking of Tgfbr1 are sensitive to MEK1/2 inhibition
