Immunohistochemistry Stain Assessment of DNA Mismatch Repair Proteins in Gastric Cancer

Abstract

Background: Germline mutations in MMR genes are reported to be present in more than 70% of HNPCC cases. But, there is a paucity of data regarding the importance of defect of MMR system in the gastric cancer in general. So, in this study, we used IHC stain forMLH1,MSH2, PMS2 andMSH6 to reveal profile ofMMR expression in patients with gastric cancer.

Materials and Methods: This study was performed on 134 patients with gastric cancer who had undergone surgical resection from January 2001 to December 2005. For comparative analyses chi-square test or Fisher's exact test and t-test were used.

Results: Through IHC assay, all of samples from patients had normal stain for MSH2 and MSH6. Except in 5 cases (3.7%) IHC stains for MLH1 and in 4 cases (3%) IHC stains for PMS2 were normal. In comparative analyses there were not any significant difference in variables between subgroups of IHC result.

Conclusion:Although, genetic factors are cause of gastric cancer in few patients, and germline mutation may increase the risk of gastric cancer. In this study 3.7% of cases with gastric cancer had abnormalMMR proteins function. It seems that MLH1 and PMS2 have a major role in MMR functions in Iranian patients with gastric cancer, to further clarify this issue, more resrarchers should be done.