| Objective Circulating miRNAs have been shown to be promising biomarkers for disease detection in recent years.Previous studies have reported miRNAs as diagnostic and prognostic biomarkers for a variety of cancers.In previous work,the differential expression technique of high-throughput miRNA microarray was used to detect that the expression of miR-642 in gastric cancer tissues was down 6.4 times compared with that in paracancerous tissues(P<0.05).These results suggest that miR-642 may play a role as a tumor suppressor gene in the pathogenesis of gastric cancer.This study aims to explore the expression of miR-642 as a biomarker in gastric cancer serum and its value in the diagnosis and prognosis of gastric cancer,as well as the effect of miRNA-642 on the proliferation and migration of gastric cancer cells,Explore the diagnostic value of using serum miRNA biomarkers to detect gastric cancer.Methods Serum samples from 378 patients with gastric cancer and 150 healthy individuals were collected in the Affiliated People’s Hospital of Inner Mongolia Medical University from December 2017 to December 2019.All patients met the diagnostic criteria for gastric cancer.1.We will randomly divided into exercise group(78 patients with gastric cancer,50 cases of healthy person)and validation group(300 cases of gastric cancer,100 cases of healthy people),using real-time fluorescent quantitative PCR(RT-PCR)detection of training and validation set of gastric cancer patients serum and healthy serum miR-642 expression differences(P < 0.05),And analyze whether its expression level is associated with clinical indicators such as age,gender,stage,prognosis,etc.in gastric cancer patients;2.Use ROC curve to compare 378 patients with gastric cancer and 150 healthy people,and analyze the diagnostic value of miR-642 as a marker for gastric cancer;3.The expression level of miR-642 in 378 patients with gastric cancer was correlated with its clinical indicators,and the relationship between the level of miR-642 expression and the prognosis and survival of patients was analyzed.4.Cultivating BGC-823 and MGC-803,three gastric cancer cell line SGC-7901,miR-642 mimics,NC transfection to gastric cancer cell lines,through Incucyte long time observation and dynamic cell function analysis system to detect the miRNA-642 mimics,NC group of gastric cancer cell proliferation of 3 days,draw the growth curve,through the changes of cell convergence degree observation of micrornas-642 mimics,NC group of the gastric cancer cell proliferation of difference(P < 0.05);MGC-803 gastric cancer cell line was cultured,and miR-642 mimics and NC were transfected into MGC-803 gastric cancer cell line.When the degree of cell confluence reached 80%-90%,the scratch test was performed.Analysis software was used to analyze the changes of cell width in the two groups within 2 days to analyze the migration of miRNA-642 mimics,NC and gastric cancer cell migration in the untreated group(P<0.05).Results Compared with the normal control group,the expression of miR-642 in serum of gastric cancer patients was significantly down-regulated.Low levels of serum miR-642 expression and tumor TNM staging Ⅲ + Ⅳperiod and a significant correlation was distant metastasis.The ROC survival curve of its diagnostic value showed that the area under the curve was 0.706,showing good sensitivity and specificity.Patients with lower serum miR-642 expression level had lower overall survival rate.In the cell function experiment,compared with the miR-642 NC group,the proliferation and migration ability of cells in the miR-642 mimics group were significantly inhibited(all P<0.05).Conclusion Our results suggest that the level of serum miR-642 is a potential biomarker for the diagnosis and prognosis of gastric cancer,and the expression level of miR-642 plays an important role in the progression of gastric cancer proliferation and migration.Mi R-642 has the potential to be a therapeutic target for gastric cancer. |
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