CTNNB1 and colorectal cancer: While genetic mutations of certain components of the Wnt/β-catenin pathway are not the predominate mechanism associated with many types of cancer including breast cancer [4], mutations of APC and CTNNB1 (β-catenin encoding gene) are two major factors for Wnt/β-catenin signaling overactivation in colorectal cancers [55, 56].