Research Article | Open Access
Implication of expression of MMR proteins and clinicopathological characteristics in gastric cancerRenu Verma1, Puja Sakhuja2, Ritu Srivastava2, Prakash Chand Sharma1
1University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India.
2Department of Pathology, Govind Ballabh Pant Hospital, New Delhi, India.
Correspondence: Prakash C. Sharma ( University School of Biotechnology, Guru Gobind Singh Indraprastha University Dwarka, Sec 16C, New Delhi 110078, India ; E-mail: firstname.lastname@example.org).
Asia-Pacific Journal of Oncology 2020, https://doi.org/10.32948/ajo.2020.12.30
Introduction Microsatellite instability (MSI), referred to as variations at microsatellite loci, at mismatch repair (MMR) genes leads to the formation of an aberrant MMR system that fails to rectify errors occurring during DNA replication. MMR deficiency can be assessed by immunohistochemical analysis of the expression of mismatch repair proteins in the target tissues.
Methods We investigated the expression of four key MMR proteins (MLH1, MSH2, MSH6, and PMS2) in formalin-fixed paraffin-embedded (FFPE) tumor and normal tissues obtained from thirty gastric cancer (GC) patients. The association of clinicopathological features with MMR status was also analyzed.
Results A total of 12 (40%) GC patients exhibited loss of expression of MMR proteins, including loss of MLH1 and PMS2 in 3 cases and loss of MSH2 and MSH6 in 4 cases. Univariate analysis showed an association of loss of MMR protein expression with moderately differentiated GC. However, there was no statistically significant association between loss of MMR protein expression with gender, tumor location, depth of invasion, lymph node metastasis, WHO classification, lympho-vascular invasion, and infection with H. pylori.
Conclusion Our results implicate the role of mismatch repair proteins in gastric tumorigenesis. The MMR protein status is an important aspect of tumorigenesis and can be prescribed for the screening of GC.
Key words Mismatch repair proteins, Immunohistochemistry, Gastric cancer, H. pylori