MUTYH and colorectal cancer: However, even though more than 80 MUTYH variants have been described in the MUTYH gene in colorectal polyposis and colorectal cancer patients (reviewed in Cheadle and Sampson, 2007; Vogt et al., 2009), the effect of only a small number of variations on human MUTYH protein activity has been investigated (Wooden et al., 2004; Bai et al., 2005; Bai et al., 2007; Ali et al., 2008; Kundu et al., 2009; Forsbring et al., 2009; Molatore et al., 2010).