Left-sided CRCs develop from benign adenomas through the conventional adenoma-carcinoma pathway typically entailing aberrant activation of Wnt signalling, most prominently via biallelic inactivation of the tumour suppressor APC, or activating mutations in CTNNB1, both of which result in the stabilization and nuclear translocation of β-catenin. This evidence concerns the gene CTNNB1 and adenoma.