Title: Loss of imprinting of IGF2 is an epigenetic marker independently associated with colorectal cancer and not related to tobacco or alcohol consumption
Abstract: Hel~ditary nonpolyposis colorectal cancer (HNPCC) results from germline mutations in the rn~nstch repair (MMR) genas, in particular MLHI, MSH2 and MSH6.HNPCC is suspected if a patient has multiple HNPCC-related cancers.Methods: 82 patients with at least two HNPCC-related cancers, at least one of which arose in the gastrointestinal tract, were included.HNPCC-related cancers were defined to inchole colorectal, endomemal, ovarian, gastric, small bowel, biliary tract, paucreatic and urothdial cancer.Mutation analysis of MLH1, MSH2 and MSH6 was performed by denaturing gradient gel electmphoresis with subsequent sequence analysis tbr small mutations and by mukiplex ligarion-dependent probe amplification for large (exonic) deletions or amplitlcationa.Clinical data were reviewed, famdy bdsto~, was obtaiued arid microsatelhie instability (MS1) analysis and immunolaistochemistry (IHC) fbr the three MMR-proteins was performed.Results: Fifteen patients were tound to carry a patbogenic gerndine mutation, 2 in MI.H1, 6 in MSH2 and 6 in MSH6.All mutation carriers were < 60 years at diagnosis of tJue first tumor and all had at least one colorectal cancer.More patients with a positive first degree family history for an HNPCC-related cancer -had a mutation than those without (12/43 vs 3/39, p<O 05) More patients with at least one MgI-high rumor carried a mutation than patients with only MSl-low tumors (12/39 vs 3/38~ p<0.05)Three MSH6 mutaticu carriers had MSl-low cancers.In evaluable tumor specimens of 28/67 patients absence of at least one MMR protein was seen by" IHC.IHC was concordant with mutatkm analysis in all 14 mutation careers, that could be evaluated Conclusion: The prevalence of germline MMR-gene mn!ations in patients whh multiple HNPCC-related cancers is high.Selection for mutation analysis is best based on age at diagnosis of the first tumor < 60, the presence of ml colorectal cancer and immunohistochemistry offbe tumor for the MMR proteins T1697