| Background and Objective:Gastric cancer is a common malignant neoplasm with low early diagnosis rate and unsatisfactory treatment results.Although its incidence rate on a world wide scale has declined,its incidence and mortality rates remain in the top three among malignant tumors within China.Therefore,the key to gastric cancer treatment are early diagnosis and comprehensive treatment.In recent years,as the surface of gene-targeted cancer therapies,the expression of related genes of gastric cancer in its tissues and serum have been investigated on the molecular level to help the early diagnosis,treatment and prognosis assessment,which will eventually improve the treatment results.miRNA is a small non-coding single-stranded RNA molecule widely found in organisms.Researches had confirmed that miRNAs had abnormal expression in tumor tissues and peripheral blood.They took part in regulating tumor-related genes,influencing the genesis,grow,invasion,proliferation,apoptosis and metastasis of tumor cells and presenting dynamic changes during different clinical stages,at different differentiation degrees and in the prognosis.This has provided theoretical bases for early diagnosis.However,miR-126,miR-199a expression pathogenesis in the occurrence and development of gastric cancer is not yet clear.The aim of this study was to explore the relationship between the expression of miR-126 and miR-199a in tissues and serum of gastric cancer and clinicopathological features,and to evaluate the diagnostic value of miR-126 and miR-199a detection in the serum,providing basis for researches on miRNAs as a biomarker for the diagnosis,to determine the condition and pathogenesis of gastric cancer.Methods:Subjects for the study group were 42 cases of gastric cancer patients with clear pathologic diagnosis from the Gastrointestinal Surgery Ward of the Second Affiliated Hospital of Nantong University from June to December 2016.The control group were 60 healthy individuals of similar age constitution and underwent physical examinations from the Physical Examination Centre of the Affiliated Hospital of Nantong University.Fresh surgical specimens,including cancer tissues and distal cancerous contrast tissues(at least 5 cm away from the cancer tissues),were collected 30 minutes after the radical gastrectomy.The diagnosis of gastric cancer were confirmed with snap freezing of the tissues and the collected tissues were preserved with liquid-nitrogen for later use.Blood(5 mL)of the patients before and one week after the operation and peripheral bloods(5 mL)of the control group were collected.miR-126 and miR-199a expressions in the tissues and serum were detected using quantitative real-time PCR.Meanwhile,peripheral bloods(5 mL)of the patients were collected before and about one week after the operation for standard carcinoembryonic antigen(CEA)test in the lab,the reference value is from 0 to 10ng/L.Results:1.For gastric cancer tissues,miR-126 expression,which was related to tumor size,clinical stage and differentiation degree,was lower in the cancer tissues(1.60±1.83)than in the distal cancerous contrast tissues(7.17±2.62)(t=7.276,P<0.05),while miR-199a expression,related to clinical stage,invasive depth and lymph node metastasis,was higher in the cancer tissues(12.04±2.27)than in the distal cancerous contrast tissues(2.12± 1.11)(t=3.908,P<0.05),The difference is statistically significant.2.For serum of gastric cancer patients,miR-126 expression in the pre-operative serum(2.49±3.36)was lower than that in the post-operative serum(7.83±2.61)(t=6.316,P<0.05);and the miR-126 expression in the post-operative serum was lower than that in the healthy control group(9.60±4.01)(t=4.338,P<0.05),while miR-199a expression in the pre-operative serum(30.04±5.04)was higher than that in the post-operative serum(14.03±6.02)(t=6.778,P<0.05);and the miR-199a expression in the post-operative serum was higher than that in the serum of the healthy control group(5.81 ±4.67)(t=7.684,P<0.05).The difference is statistically significant.The former was related to tumor clinical stage and differentiation degree and the latter to clinical stage and invasive depth.3.The AUC of the ROC Curve of diagnostic efficiency of miR-126 expression was 0.823 in gastric cancer tissues and 0.776 in serum while those of miR-199a expression were respectively 0.862 and 0.918.The AUC of CEA diagnostic efficiency was 0.537.4.Pearson correlation analysis showed that the correlation coefficient of miR-126 expression in cancer tissues and pre-operative serum of gastric cancer patients was 0.484,while the correlation coefficient of miR-199a expression in cancer tissues and pre-operative serum of gastric cancer patients is 0.65,P<0.01.Both had positive correlation.Conclusions:1.miR-126 expression was down-regulated and miR-199a expression was up-regulated in gastric cancer tissues and serum,both were related to the occurrence and development of gastric cancer.2.miR-126 expression in the serum of gastric cancer patients was related to clinical stage and differentiation degree and miR-199a expression was related to clinical stage and invasive depth.miR-126 and miR-199a expressions in the serum can be used as an indicator for the severity of gastric cancer.3.miR-126 and miR-199a expressions in serum both had desirable diagnostic values of gastric cancer,better than the serum CEA test.Their expression levels in tissues and serum were positively related,and they may become valuable biomarkers for diagnosing gastric cancer. |
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