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. Author manuscript; available in PMC: 2008 Nov 24.
Published in final edited form as: Drug Discov Today Dis Mech. 2007;4(4):293–300. doi: 10.1016/j.ddmec.2008.05.004

Figure 2. Genetic Testing Approach for Lynch Syndrome.

Figure 2

There are several approaches to determine who should have genetic testing for hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome. If Amsterdam II criteria are met (see Table 4), one may proceed directly to germline genetic testing. If there is a strong family history of colon cancer, but these criteria are not met, the Bethesda Guidelines should be applied. If any of these are met, the tumor should be tested for microsatellite (MSI) instability and/or tumor immunochemistry (IHC) should be done. IHC examines the expression of the mismatch repair genes. If MSI is positive or IHC testing indicates lack of expression of one of the mismatch repair proteins, then one should proceed to germline genetic testing. This testing usually involves a peripheral blood draw and lymphocyte DNA for the testing. (Modified from [27]