The first review study on association of DNA methylation with gastric cancer in Iranian population.
BACKGROUND
Gastric cancer (GC) is the second leading cause of cancer-related death worldwide. Several environmental, genetic and epigenetic factors have been suggested to have a role in GC development. Epigenetic mechanisms like histone changes and promoter hyper-methylation are now being increasingly studied. Associations between methylation of many gene promoters with the risk of gastric cancer have been investigated worldwide. Such aberrant methylation may result in silencing of specific genes related to cell cycling, cell adhesion, apoptosis and DNA repair. Thus this molecular mechanism might have a key role in proliferation and migration of cancerous cells.


METHODS
In this review article we included studies conducted on DNA methylation and gastric cancer in Iranian populations. Using Science direct, Pubmed/PMC, Springer, Wiley online library and SciELO databases, all published data until 31 January 2016 were gathered. We also searched Science direct data base for similar investigations around the world to make a comparison between Iran and other countries.


RESULTS
By searching these databases, we found that the association between methylation of seven gene promoters and gastric cancer had been studied in Iran until 31 January 2016. These genes were p16, hLMH1, E-cadherin, CTLA4, THRβ, mir9 and APC. Searching in science direct database also showed that 92 articles had been published around the world till January 2016. Our investigation revealed that despite the importance of GC and its high prevalence in Iran, the methylation status of only a few gene promoters has been studied so far. More studies with higher sample numbers are needed to reveal the relation of methylation status of gene promoters to gastric cancer in Iran.


CONCLUSIONS
Further studies will be helpful in identifying associations of DNA methylation in candidate genes with gastric cancer risk in Iranian populations.
School of Veterinary Medicine, Razi University, Varamin, Iran E-mail : kyari@kums.ac.ir.
Mahsa
M
Shahbazi
Kheirollah
K
Yari
Niloufar
N
Rezania
D014408:Biomarkers, Tumor / Q000235:genetics*; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics; D006801:Humans; D007492:Iran / Q000453:epidemiology; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000235:genetics; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000235:genetics*
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm