In some adenomas of the colon, intestinal crypt cells appear to have proliferated abnormally to form small tumors known as polyps. Studies on the familial type of such a disease led to the identification of a major signaling pathway (which was aberrant in the polyp cells) as being involved in the maintenance of the gut stem-cell compartment. What signaling pathway is this? Is it upregulated or downregulated in colon cancers?