Determination of MicroRNAs in plasma as diagnostic biomarkers in gastric diseases due to Helicobacter pylori

Gastric cancer (GC) is one of the malignancies that is increasing in frequency worldwide and causes serious health problems. Helicobacter pylori (H. pylori) infection stands out as an important risk factor in the etiology of this disease. Chronic inflammation caused by H. pylori initiates and progresses the cancerous process in the gastric mucosa through both genetic and epigenetic mechanisms. In recent years, MicroRNAs (miRNAs) have attracted attention as potential biomarkers in determining the early diagnosis and prognosis of diseases. In this study, the expression levels of miR-106b and miR-25 in H. pylori-associated gastric diseases (ulcer, gastritis and GC stages) were evaluated and the diagnostic potential of these miRNAs was investigated. For this purpose, 3 mL peripheral blood samples were collected from 30 individuals, including 10 GC patients who were clinically diagnosed as H. pylori positive, 10 ulcer/gastritis patients, and 10 healthy H. pylori negative individuals (controls). The samples were stored at -80 °C. miRNA isolation was performed using the Nepenthe kit, and then cDNA synthesis was performed from the obtained miRNAs. Gene expression levels were quantitatively analyzed by Real-Time PCR (qRT-PCR) method using miR-106b and miR-25 specific primer sequences. As a result of the study, it was observed that the expression levels of miR-106b and miR-25 increased in the ulcer and gastritis group compared to the control group, but this increase was much more pronounced in the GC group. The obtained data suggest that these miRNAs may play a role in the pathogenesis of gastric diseases and have the potential to be evaluated as diagnostic biomarkers, especially in the early stages of the disease. In this context, studies supported by larger sample groups and advanced molecular analyses will more clearly explain the usability of miR-106b and miR-25 in clinical applications. Keywords: Biomarker, Gastric Cancer, H. pylori, MicroRNA