Review Article: The Lynch Syndrome (hereditary Nonpolyposis Colorectal Cancer)

Background: The most common inherited colorectal cancer syndrome is the Lynch syndrome (HNPCC) which is characterized by the development of colorectal, endometrial, and other cancers and the presence of microsatellite instability (MSI) in tumours. The syndrome is due to a mutation in one of the mismatch repair (MMR) genes: MSH2, MLH1, MSH6 and PMS2.

Aims: To evaluate the clinical features of the Lynch syndrome and to assess the tools that are available for the identification of families with this syndrome.

Methods: A systematic literature search using PubMed and reference lists of retrieved articles was performed.

Results: The review provides an update of the clinical phenotype of the Lynch syndrome. Until recently, the Amsterdam criteria were the most important tool for the identification of Lynch syndrome. Nowadays, the Bethesda guidelines are more widely used. These guidelines describe all clinical conditions in which a search for MSI indicated. Both MSI-analysis as well as immunohistochemical analysis of the MMR-proteins are appropriate to identify patients with a high probability of carrying a MMR-gene mutation.

Conclusion: All specialists that are involved in the treatment of cancer patients should know the Bethesda criteria in order to identify all families suspected of the Lynch syndrome.