The Expression Of Serum MiR-551b-3p In Gastric Cancer And Its Clinical Significance

Background/Objective: Gastric cancer is one of the most common malignant tumors of digestive system in the world.Gastric cancer has attracted much attention because of its high morbidity and mortality The early diagnosis and treatment of gastric cancer is the key to solve the difficult problem.However,the current invasive gastroscopy is difficult to popularize and the traditional and most widely used tumor biomarkers are relatively less specific and sensitive for the diagnosis of gastric cancer.Because of miRNAs stable existence in body fluid,they had the potential to be ideal circulating tumor biomarkers and had been a hot spot in recent years.The objective of this study was to investigate the expression of miR-551b-3p in serum of gastric cancer patients and to compare the changes of serum miR-551b-3p expression in gastric cancer patients and healthy controls.We analyzed the correlation of serum miRNA-551b-3p expression and the clinicopathological parameters of gastric cancer patients,and explored its clinical significance for the diagnosis of gastric cancer.Methods: In this study,serum samples of 50 patients with pathologically diagnosed gastric cancer and 53 healthy individuals were collected.Total RNA was extracted from serum of patients with gastric cancer and healthy controls by Trizol.Reverse transcription was performed.We used miR-16 as an internal control in this study.The expression of mi R-551b-3p in serum was detected by real-time fluorescence quantitative PCR(qRT-PCR).We compared the serum expression of miR-551b-3p in gastric cancer patients and normal controls.The difference between the expression of miR-551b-3p and the clinicopathological characteristics of gastric cancer patients was analyzed.Results:(1)The expression of miR-551b-3p in serum of patients with gastric cancer was significantly lower than healthy controls(P = 0.000).(2)The low level of serum miR-551b-3p in patients with gastric cancer was significantly correlated with tumor diameter(P = 0.014),depth of invasion(P = 0.001)and TNM stage(P =0.022).And there was no significant correlation with age,gender,tumor differentiation and lymph node metastasis(P> 0.05).(3)The diagnostic efficacy of serum miR-551b-3p as a diagnostic biomarker for gastric cancer: The area under the ROC curve was 0.860,P = 0.000(95% confidence interval:0.787-0.933),Youden index was 0.662.The best cutoff was 0.0175.When the relative expression level of serum miR-551b-3p in gastric cancer patients was lower than the cut off,the sensitivity was 70%,the specificity was 96.2%,the misdiagnosis rate(?)was 3.8%,the omission diagnostic rate(?)was 30%,the diagnostic coincidence rate(?)was 83.5%,the positive predictive value(PV+)was 94.6%,the negative predictive value(PV-)was 77.3%.The results of the consistency test with the current gold standard of gastric cancer diagnosis indicated kappa value was 0.667(P= 0.000).(4)The diagnostic efficacy of serum miR-551b-3p in the diameter of gastric cancer was evaluated: the area under the ROC curve was AUC=0.702,P=0.014(95% CI: 0.556-0.847),the sensitivity was 80.8% and the specificity was 58.3%;Infiltration depth diagnostic evaluation:AUC=0.792,P=0.000(95% CI: 0.652-0.929),the sensitivity was 87.1% and the specificity was68.4%;Evaluation of clinical TNM staging effectiveness: AUC=0.690,P=0.022(95% CI:0.543-0.836),the sensitivity was 90.9% and the specificity was 53.6%.Conclusion: The expression of serum miR-551b-3p in patients with gastric cancer is significantly lower than that healthy controls.The expression of miR-551b-3p is significantly correlated with tumor diameter,depth of invasion and TNM stage,and its diagnostic accuracy and the diagnostic consistency for gastric cancer is good.Serum miR-551b-3p also has certain diagnostic value for tumor diameter,depth of invasion and TNM stag of gastric cancer.Therefore,serum miR-551b-3p has important reference value for the clinical diagnosis of gastric cancer.