Mutations of hMSH2 gene and hMLH1 gene in human colovectal carcinomas

Mutations of the hMSH2 and hMLH1 mismatch repair system genes in hereditary non-polyposis colorectal cancer (Lynch) syndrome as well as sporadic colorectal cancers with microsatellite instabilities are overviewed. Alterations of genes involved in DNA repair would be the cause of genetic instability, increase of mutation rate as well as elevation of cancer risk. In addition, the recent topics of frequent association of TGF-beta type II receptor gene insertion/deletion mutation and replication error positive colorectal cancers are also discussed.