A research team has analyzed the three-dimensional structure of a protein that suppresses the development of colorectal polyposis, MUTYH, at the atomic level and clarified the repair mechanism for DNA mispairings. Since mutations in the MUTYH gene cause heritable colorectal polyposis, which leads to colorectal cancer, the researchers expect that this work will be useful for future research on heritable colorectal polyposis associated with MUTYH.