Lynch syndrome is one of the most common inherited predisposition syndromes which demonstrated autosomal dominant manner and is associated with increased risks of colorectal and endometrial cancer, as well as multiple other cancer types. Lynch syndrome is caused by germline pathogenic variants in any of 4 DNA mismatch repair(MMR)genes MLH1, MSH2, MSH6 or PMS2 and rarely in the non-MMR gene EPCAM, in which deletion of its last exon induce epigenetic silencing of MSH2. Resent advances have been occurred in our understanding of the epidemiology of this disease and the advent of multigene panel tests brought more understanding of the pathogenesis of neoplasia in the setting of Lynch syndrome and these advances have important implications of prevention, risk-reduction and immunotherapy.