Link between miR-19b and the mTOR signaling pathway in cancer prognosis*

Abstract Objective Previous studies have reported differing conclusions regarding the prognostic value of miR-19b in cancers. Moreover, miR-19b may affect tumor growth by different pathways, mainly targeting PTEN-PI3K-AKT, which activates the downstream mTOR pathway. Therefore, we performed data mining to explore the possible correlation between miR-19b and mTOR in cancer prognosis. Methods We conducted online search and collected a total of 943 articles. According to different authors cross check and our study including/excluding criteria we at end retained 21 articles with 25 studies in this meta-analysis. Then TCGA data containing miR-19b level with cancer progression were obtained using OncomiR. Furthermore, Trial Sequential Analysis (TSA) was performed to determine whether the results of our meta-analysis could be used in clinical applications. After that, articles regarding the mechanism of miR-19b in various cancers were analyzed and KEGG pathway database was used to find the main regulatory function of miR-19b in human cancers. Results Overall hazard ratio (HR) results showed that higher levels of miR-19b expression were correlated with shorter overall survival time [HR = 1.54, 95% confidence interval (CI) = 1.20-1.98] by promoting distant metastasis, but had no correlation with disease-free survival (DFS)/progression-free survival (PFS; HR = 0.61, 95% CI = 0.31-1.19). Data from The Cancer Genome Atlas also revealed the role of miR-19b in tumorigenesis. According to trial sequential analysis results, more evidence is required to confirm that miR-19b is not correlated with DFS/PFS. Exploration of the mechanism revealed a possible link between miR-19b and the mTOR pathway. Conclusion miR-19b may have a pro-carcinogenic role through the mTOR pathway and thus, it is likely to be a therapeutic target for cancers.