Expression of miRNA-146a, miRNA-155, IL-2, and TNF-α in inflammatory response to Helicobacter pylori infection associated with cancer progression.

miRNAs appear to play an important role in controlling the expression of several genes, and they are a potential biomarker and prognostic tool in gastric diseases. We analyzed 53 controls, 86 patients with gastritis, and 19 patients with gastric cancer. Real-time-PCR was used to determine the expression levels of miRNA-146a, miRNA-155, IL-2, and TNF-α. The subsequent analysis of the target genes was performed using the bioinformatics approach. There was no difference in IL-2 expression between the groups. However, there was a significant increase in TNF-α expression in the gastritis group relative to the control and a significant decrease in the gastric cancer group relative to the control. There was also a statistically significant increase in miRNA-146a and miRNA-155 expression in the gastritis group relative to the control, but not in the gastric cancer group. Similar results were found when the presence of H. pylori was considered. The data revealed an increase in miRNA-146a and miRNA-155 expression but not enough to control the expression of TNF-α. The presence of H. pylori was found to affect increases in TNF-α and microRNA expression, and miRNA-146a and miRNA-155 alone were not able to eliminate bacteria or restore tissue homeostasis.