However, little is known about the relationship between lung cancer risk and germline mutations that underlie common hereditary cancer syndromes, such as Lynch syndrome, which is caused by mutations in DNA mismatch repair (MMR) genes including MSH2, MSH6, MLH1, and PMS2. Individuals harboring germline loss-of-function variants in MMR genes have an elevated risk of specific cancer types, especially colorectal, endometrial, and gastric carcinomas. This evidence concerns the gene MLH1 and lung cancer.