APC and adenoma: However, several groups have reported that nuclear localization of β-catenin, which is required to activate Wnt target genes, is infrequently observed in early adenomas of patients with FAP, sporadic human polyps and microadenomas in a rat model of FAP, despite Apc loss of heterozygosity (LOH) and elevated cytosolic β-catenin (Amos-Landgraf et al., 2007; Anderson et al., 2002; Bläker et al., 2004; Kobayashi et al., 2000).