In the 100kGP cohort, alterations of RNF43 or CTNNB1 are found in a minority of sporadic colorectal cancers, mostly microsatellite unstable (MSI), and are mutually exclusive with APC inactivation in MSS tumors (OR = 0.019, P = 3.94 × 10−24 and OR = 0.15, P = 1.46 × 10−5, respectively, Fig. 5A; Supplementary Table S12), suggesting an upper bound on WNT activity. This evidence concerns the gene CTNNB1 and colorectal cancer.