Alcohol intake is associated with the production of reactive oxygen species—including oxygen radicals, lipid peroxidation, and acetaldehyde—which cause DNA damage that can be repaired by the DNA base-excision repair pathway.22 Therefore, polymorphisms of the base-excision repair gene (XRCC1) may be a risk factor for colorectal cancer and modify the association between alcohol consumption and colorectal cancer risk. The gene discussed is XRCC1; the disease is colorectal cancer.