Expression of microRNAs in gastric cancerous tissues and their association with Helicobacter pylori and Epstein‑Barr virus infections

Abstract

Gastric cancer (GC) is a serious public health concern, being one of the most frequent types of cancer worldwide, and the most lethal of all gastrointestinal cancers. Among the numerous causes of the occurrence and progression of GC, are infections of the gastric epithelium by microbial agents, such as Epstein‑Barr virus and/or <em>Helicobacter pylori</em> (<em>H. pylori</em>). Recent findings have shed new light on the involvement of a class of non‑coding RNAs, known as microRNAs (miRNAs/miRs) that are differentially expressed in GC tissues. Among these miRNAs, miR‑21, miR‑223 and miR‑19, appear to play a crucial role in tumorigenesis. The present study aimed to investigate the differential expression of miR‑21, miR‑223 and miR‑19 in GC tissues and their association with Epstein‑Barr virus and <em>H. pylori</em> infections. The expression levels of miR‑21, miR‑223 and miR‑19 in 70 samples of cancerous and adjacent normal tissues from patients with GC were detected using reverse transcription‑quantitative polymerase chain reaction. The clinical relevance was then statistically analyzed. The results revealed the overexpression of the three miRNAs, miR‑21, miR‑223 and miR‑19, in tumor tissues compared to the corresponding normal tissues. In addition, the upregulation of the mentioned miRNAs in GC tissues was also significantly associated with Epstein‑Barr virus and <em>H. pylori</em> infections, as well as with aggressive clinicopathological features. On the whole, the findings of the present study indicate the potential of miR‑21, miR‑223 and miR‑19 for use as novel diagnostic, prognostic and predictive biomarkers for gastric tumors. However, further randomized studies involving diverse populations and functional assessments are required to extend and confirm these findings.