[Management of hereditary non-polyposis syndrome (Lynch syndrome)].

Genetic background is suspected in about 20% of colorectal cancer (CRC) cases, in which either genetic polymorphisms or Mendelian heritable factors are involved. Currently known CRC syndromes include various polyposis syndromes (<1% of total CRC cases) and Lynch syndrome (LS), previously termed hereditary nonpolyposis colorectal cancer (HNPCC, comprises 3-5% of all CRC cases). LS is caused by dominantly inherited mutations in the mismatch repair genes MLH1, MSH2, MSH6 or PMS2, and results in a very high lifetime risk (approximately 80%) for CRC and significantly increased risk for extracolonic tumors in regions such as the endometrium, ovary, urinary tract, lymphoma, stomach, pancreas small bowel and brain.