Highly Sensitive Multiplexed Sensing of miRNAs in a Gastric Cancer Patient's Liquid Biopsy

Gastric cancer (GC) is one of the leading causes of cancer mortality in the world. Most patients are in the advanced stage of the disease at the time of diagnosis because the symptoms of early gastric cancer patients are not obvious. Early diagnosis of gastric cancer is still challenging due to the high cost, invasiveness, and low accuracy of traditional diagnostic methods such as endoscopy and biopsy. Herein, we develop clinically accurate and highly sensitive detection of multiple GC miRNA biomarkers in human serum using an isothermal nucleic acid primer exchange reaction (PER). The isothermal nucleic acid primer exchange reaction demonstrates high sensitivity and robustness, exemplified by a one-pot reaction achieving a detection limit of 28.71 fM. By quantifying the levels of three miRNA biomarkers selected through bioinformatics analysis in gastric cancer serum samples, the diagnostic approach effectively distinguished between clinical gastric cancer patients (n = 25) and noncancer controls (n = 10). The performance of our three-miRNA signature in discriminating between GC and controls was as follows: area under the curve (AUC): 0.808, sensitivity: 89%, specificity: 88%, positive predictive value (PPV): 96%, and negative predictive value (NPV): 70%.