Hereditary nonpolyposis colon cancer: Revised Bethesda criteria, immunohistochemistry, microsatellite instability, germline analysis, and emerging issues in genetic testing
ABSTRACT Clinical criteria aid in the decision to pursue genetic testing for suspected cases of hereditary nonpolyposis colon cancer
(HNPCC) and continue to be refined. Sequence analysis offers the greatest opportunity for definitive germline mutation testing;
however, prescreening through microsatellite instability and/or immunohistochemistry offers a cost effective alternative,
and recent studies suggest both are complementary. BRAF mutations and hMLH1 promoter methylation appear to have negative predictive value for identifying individuals with HNPCC, but further studies
are needed. We review strategies for the evaluation of suspected HNPCC, as well as emerging issues in testing.