Overall, the intimate relationship between defective DDR and cancer is clearly underlined by the numerous human genetic diseases that are associated with both DDR defects and predisposition to cancers including xeroderma pigmentosum, familial breast cancer, Bloom syndrome, MYH-associated polyposis, hereditary nonpolyposis colorectal cancer, etc. [59]. The gene discussed is MUTYH; the disease is xeroderma pigmentosum.