Molecular Stratification of Sporadic and Hereditary Colorectal Cancer – Mini Review

Colorectal cancer (CRC) is one of the most common cancers and one of the leading causes of cancer death in the Western world. The disease arises from the accumulation of mutations in oncogenes, tumor suppressor genes and mismatch repair genes during progression from normal colon epithelium to adenoma and metastatic carcinoma. The majority of colorectal cancers arise in sporadic form. About one-third of patients with CRC have a family history of cancer and elevated risk for this malignant disease. However, only 5% of CRC arise from a germline mutation in high penetrant genes, adenomatous polyposis coli (APC) gene and DNA mismatch repair (MMR) genes. The most common hereditary CRC syndrome is Lynch syndrome defined by hereditary germline mutations in one the of MMR genes. The term hereditary non-polyposis colorectal cancer (HNPCC), previously used interchangeably with Lynch syndrome, now refers to a broader spectrum of familial CRC disorders that can mimic some clinical features of Lynch syndrome, but without germline mutations in MMR genes characteristic for Lynch syndrome. Distinguishing between the HNPCC disorders is important for clinicians, as the approach to surveillance for patients and their family members differs according to risk for CRC associated with each syndrome. This mini review will give some information about the most frequent molecular genetics changes in sporadic and hereditary colorectal cancer and its molecular stratification due to its heredity, somatic mutations and microsatellite instability.