Does MiRNA gene expression predict gastric cancer stage and localization?

Abstract

Gastric cancer comprises 10% of all cancers in the world and is rarely seen before the age of 30. Different genetic interactions or molecular changes like e-cadherin, P16, APC, c-erb B2, c-met, ras, or c-myc have been described in the pathogenesis of the disease. MiRNAs play critical roles in various biological processes such as cell proliferation, cell differentiation, apoptosis, repairing of DNA damage, angiogenesis, stress response, and stem cell division. The aim of this study is to investigate the relationship between miRNA gene expressions and gastric cancer. Method: Sixty-four patients with gastric cancer diagnosed consecutively in our pathology laboratory and 30 consecutive participants with normal gastric tissue, as a control group, were included in our study between 2011 and 2013. Total miRNAs were obtained by using genomic miRNA extraction kit (QIAGEN Sample & Assay Technologies, Hilden, Germany) after the samples had been deparaffinized. MiR-21, 107, 141, 150, 192, 202, 218, 331 gene expressions were evaluated by using real time-PCR (RT-PCR) from the whole miRNA. Results: MiR-331 was downregulated in the stage 2 patients and the rest of the miRNAs were significantly upregulated (p < 0.001). All miRNAs were significantly upregulated in the stage 3a patients (p < 0.001). In the antrum localized tumors, miR-107, -150, -202, -218, and -331 were significantly upregulated, whereas miR-21, -192 were statistically downregulated (p < 0.05). In the cardia localized tumors, miR-21 (p > 0.05) was downregulated and miR-107, -150, -202, -218, and -331 were upregulated (p < 0.05) Different gene expressions of miRNAs according to the different localizations of gastric cancer and different stages suggest that it can be tumor marker to predict the stage and localization of gastric cancer.