The type 2 MUTYH protein is a nuclear form of MUTYH [4–6], and somatic APC (MIM #611731) and KRAS (MIM #190070) mutations occur in the nuclear DNA of MAP tumors [9, 10, 33]; therefore, we believed that it would be more appropriate to use type 2, rather than type 1, in a comparative study of MUTYH variants, and we analyzed the DNA repair function of the variant type 2 form in vitro and in vivo in this study. The gene discussed is APC; the disease is mutyh-associated polyposis.