Currently, qualifying the up and down-regulated of miRNAs for the assessment of gastric precancerous lesions, have also been proposed but not implemented routinely. Studies have evaluated the diagnostic and prognostic value of miRNAs in human gastric cancer with the method of meta-analysis or in systematic reviews[24].Several miRNAs, such as miR-21, miR-17-5p, etc, which have been proved to be potential biomarks for gastric cancers.With the method of meta-analysis, we evaluate the diagnostic and prognostic value of miR-92a in gastric cancer at present study.The results of the study showed that different assay type, type of the sample and sample size did not have a significant effect on the overall diaganostic accuracy. Besides, more moderate specificity and sensitivity in the diagnosis of gastic cancer have been found.And we expand the number of articles for diagnostic value compared with Wei H et al and Liu H et al’s studies[24, 25]. In the pronostic value, patiens who are with high expression of miR-92a have more longer OS compared with low expression.On a par with Ren C et al’s study[26], which only included two studies that investigated the prognostic value of miR-92a in gastric cancer, the present study included more articles, thus could greatly enhance the reliability of the results.
The significant role of miR-92a has been found in several cancers, one study indicated that overexpression of miR-92a is associated with osteosarcoma, colorectal cancer, non-small cell lung cancer or hepatocellular carcinoma[27].However, in gastric cancer, few schloars still have definite statements on the specific role of miR-92a desperately. Liu H [24]et al’s study combined multi-miRNAs showed that the expression of miR-92a was increased inthe serum sample of gastric cancer. Patients with high miR-92a expression have a short survival time[27].But in opposite, one study[28] indicated that levels of miR-92a may be not related to gastric cancer, which found that contrasting results.Recently, Hideyuki Ohzawa et al [29] and Soeda N[30] et al’s studies provide a new method for the prediction of gastric cancer, which regard the exosome miR-92a as a biomraker for the diagnosis tool of gastric cancer.And they revealed the same results that gastric cancer patients with high expression of miR-92a and shorter overall survival time. Collectively, these conflicting results indicate the need for further studies on the role of miR-92a.
The diagmostic value of miR-92a has been demenstrated in several studies. With a sensitivity and specificity of 76% and 75%, Peng Q et al[31]found that vary expression between the patients with colorectal cancer and healthy controls.Moreover, their experiment indicated that the miR-92a-related combination markers achieved a higher level of diagnostic power.miR-92a also presented high accuracy of diagnosis for cervical cancer, with the sensitivity and specificity were 70% and 80%, respectively[32].For gastric cancer, the diagnostic accuracy of miR-92a varied significantly,with a sensitivity ranging from 39.3–97.5% and a specificity ranging from 70.8–97.8%.In addition, there are differences among these studies, such as assay type for qT-PCR, type of the sample and sample size.We found that miR-92a’s high accuray of diganosis regardless of these differences.The results indicates that miR-92a can be used as a diagnostic indicator for gastric cancer.
For prognostic value of miR-92a, we founded that high expression of miR-92a may not be associated with poor clinical outcomes of gastric cancer patients, which was 1.46-fold higher risk for poor OS in both univariate and multivariate studies.However, untill we have finished extracting the articles, we have not found any the data of DFS(Disease free survival) and PFS(Progression-free survival) for miR-92a in gastric cancer. Currently, non-invasive biomarkers are more and more popular for assessing survival prognosis at any time before or after treatment.In our study, we have not obvious prognostic effect on gastric cancer, which is inconsistent with previous results of some previous prognostic studies, while our study may is the first one to report there is a negative association between high expression of miR-92a and patient survival.However, our sample size are larger than previous meta-analysis.In order to clarify the reults, more researches with sufficient data need to be done in the future.