Correlation of serum exosomal miR-21 with the risk of gastric cancer onset: its value for early diagnosis.

OBJECTIVES: This research explored the connection between serum exosomal miR-21 expression and the risk of gastric cancer (GC), and evaluated the viability of using this non-invasive marker for early GC diagnosis. METHODS: A retrospective evaluation was performed on 539 individuals who had received serum exosomal miR-21 testing. Based on diagnoses within 12 months, patients were categorized into a GC group (n=235) and a non-GC group (n=304). To measure the levels of exosomal miR-21, we used the technique of reverse transcription quantitative polymerase chain reaction (RT-qPCR). RESULTS: The GC group had significantly higher body mass index (BMI), rates of manual labor, smoking, drinking, high-salt/pickled diet, chronic gastritis, Helicobacter pylori (Hp) infection, and family history of GC (all P<0.05). The laboratory findings indicated that the GC group exhibited significantly higher levels of white blood cell count, platelet count, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, creatinine, carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, CA 72-4, and serum exosomal miR-21 levels, but lower levels of hemoglobin, total cholesterol, and triglyceride (all P<0.05). Logistic regression revealed that high miR-21 constitute an independent risk factor for GC (OR=3.477, P<0.001). Receiver operating characteristic for early GC diagnosis showed an area under the curve of 0.772 for miR-21 alone, and a combined model with CA72-4 increased it to 0.927. The high miR-21 group demonstrated a markedly greater GC incidence (P<0.001). CONCLUSIONS: Serum exosomal miR-21 is linked to GC and demonstrates potential as a non-invasive biomarker for early detection, particularly when combined with CA72-4.