Analysis Of Micrornas In Gastric Juice And Its Significance In Gastric Cancer Screening

ObjectiveFor screening early-stage gastric malignancies, the commonly used serum biomarkers havelimited enough sensitivity and specificity. MicroRNAs (miRNAs) play important roles intumorigenesis and metastasis. The previous studies of our group have shown that altered gastriccancer-specific miRNAs expression in gastric cancer tissues and peripheral blood of patients withgastric cancer. However, the majority of cancer-specific miRNAs are lack of tissue-specifivity.How to use these miRNAs to determin the soures and type of tumor is a puzzle. In view of thetissue-specific of gastric juice and the role of miRNAs in tumorigenesis, in this study, we intend toanalyze the existence of gastric juice miRNA. And then establish the method of detection of gastricjuice of miRNA. Finally, comparing the levels of gastric juice miRNAs in healthy people, patientswith benign gastric diseases and patients with gastric cancer to discover the law of gastric juicemiRNA expression and provide a new non-invasive screening way for the diagnosis of gastriccancer.Methods1. Confirm the existence and stability of miRNAs in gastric juice by real-time quantitativereverse transcription-polymerase chain reaction (RT-qPCR) and sequencing.2. Gastric juices from141patients including42gastric cancer,34gastric ulcer,18atrophicgastritis, and47patients with normal mucosa or minimal gastritis were collected by gastroscopy.Ten pairs of gastric cancer and adjacent normal biopsy specimen were also collected. Detection theexpression levels of gastric cancer tissues and juice by using RT-qPCR.3. The receiver operating characteristic (ROC) curve was constructed for evalution thediagnosis value and finding the suitable cut-off value.4. Analysis the relationship between gastric juice miRNA levels and clinicopathologic factors.Comparing with the commonly used tumor markers, the diagnostic value of gastric juice miRNAwas comprehensive assessmented.Results1. MiRNAs existed in gastric juice and maintained stable at least within12hours when thespecimens were placed in different external environments. 2. The levels of miR-21and miR-106a in gastric cancer tissues were significantly highercompared with adjacent tissues. However, patients with gastric cancer had significantly lowerlevels of gastric juice miR-21and miR-106a compared with patients with benign gastric diseases.3. The areas under ROC curve (AUC) were0.969(P<0.0001) and0.871(P<0.0001) formiR-21and miR-106a, respectively. The optimal cut-off values (ΔC_q) were-2.73and2.61,respectively. The gastric juice miR-21and miR-106a levels in male patients with gastric cancerwere significantly lower than those in female patients (P=0.015). There were significantcorrelations between gastric juice miR-21/miR-106a levels from gastric cancer patinets and theirBorrmann types.4. Gastric juice miRNAs had a higher diagnostic effectiveness and positive rate comparedwith serum tumor markersConclusionsBy researching the existence and stability of gastric juice miRNA, gastric juice miRNAs wereable to use as the precondition of gastric cancer biomarker. Through analyzing the clinicalspecimen,we definited the diagnosis value of gastric juice miRNAs and found that gastric juicemiRNAs are better than traditional serological markers in the screen of gastric cancer.