APC and neoplasm: Importantly, these cell lines represent a diversity of tumor types: the first four cell lines contain mutations in APC, the most common activating mutation of the Wnt/β-catenin pathway in CRCs; in contrast, HCT116 and LS174 have direct activating mutations in CTNNB1, the gene that encodes β-catenin, while RKO cells have intact Wnt/β-catenin signaling.