Lynch-like syndrome (LLS) is associated with an incomplete understanding of its molecular basis. Some LLS tumors harbor somatic variants in mismatch repair genes, whereas germline variants in other DNA repair genes point to a hereditary predisposition in certain cases. Clinically, LLS patients tend to develop colorectal cancer (CRC) earlier, have a stronger family history of CRC, and respond better to immunotherapy compared with sporadic CRC cases. This study seeks to identify cancer-susceptibility genes in LLS patients, which could affect diagnosis, treatment, and surveillance.