History and pathogenesis of lynch syndrome.

Lynch syndrome is the familial clustering of colorectal and endometrial cancers. This syndrome is passed in an autosomal dominant fashion within families with defective mismatch repair as the genetic basis for cancer development in these patients. There remains a group of patients who fit clinical diagnostic criteria for an autosomal dominant familial cancer syndrome, which is phenotypically similar to Lynch syndrome, but for which no mismatch repair mutation is identified. Identification of alternate genetic mutations such as EPCAM and CHEK2 may explain the cancer risk in a small subset of these patients, but continuing work into the genetic basis of colorectal familial cancer syndromes is needed.