Lynch syndrome (LS), an autosomal dominant familial cancer syndrome, is caused by inherited mutations in five genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) that disrupt the mismatch repair (MMR) pathway. This disruption causes microsatellite instability (MSI) that may lead to oncogenesis. Lynch syndrome accounts for about 3% of all colorectal cancer (CRC) cases and is associated with increased risk of gastric, brain, upper urinary tract, and endometrial cancer in women.