BackgroundPrevious studies showed the aberrant expression of microRNA-182 (miR-182) in glioma tissue. However, the exact role of circulating miR-182 in glioma remains unclear. Here, we confirmed the expression of plasma circulating miR-182 in glioma patients, and further explored its potential diagnostic and prognostic value.Material/MethodsReal-time quantitative PCR (RT-PCR) was used to measure circulating cell-free miR-182 from 112 glioma patients and 54 healthy controls.ResultsOur findings showed that the level of circulating miR-182 in glioma patients was higher than that in healthy controls (P<0.001), which was significantly associated with KPS score (P=0.025) and WHO grade (P<0.001). The area under the receiver operating characteristic (ROC) curve (AUC) was 0.778. The optimal cut-off value was 1.56, and the sensitivity and specificity were 58.5% and 85.2%, respectively. Interestingly, a high predictive value of circulating miR-182 was observed in high-grade glioma (AUC=0.815). However, the AUC was lower in low-grade glioma (AUC=0.621). Kaplan-Meier analysis demonstrated that the cumulative 5-year overall survival rate in the high miR-182 group was significantly lower than that in the low miR-182 group in both overall survival (OS) (P=0.003) and disease-free survival (DFS) (P=0.006). Moreover, multivariate Cox analysis revealed that circulating miR-182 was an independent prognostic indicator for OS (P=0.034) and DFS (P=0.013).ConclusionsThese results suggest that circulating miR-182 may be a potential noninvasive biomarker for the diagnosis and prognosis of human glioma.

Lung adenocarcinoma (LUAD) is the most commonly diagnosed type of lung cancer and exhibits a high morbidity. The present study aimed to investigate the long non-coding RNA (lncRNA)-associated competing endogenous RNA (ceRNA) mechanisms in LUAD. The receptor activity modifying protein 2-antisense RNA 1 (RAMP2-AS1) was identified using GSE113852 and GSE130779 datasets downloaded from the Gene Expression Omnibus database, and the downregulation of RAMP2-AS1 was the most significant in LUAD. In addition, microRNA (miR)-296-5p was identified to bind to RAMP2-AS1 via bioinformatics analysis. Subsequently, CD44, cyclin D3 (CCND3), neurocalcin δ (NCALD), microtubule actin crosslinking factor 1 (MACF1) and potassium channel tetramerization domain containing 15 were obtained by intersecting the predicted target genes of miR-296-5p and 368 differentially expressed mRNAs in LUAD. According to the Gene Expression Profiling Interactive Analysis and UALCAN databases, these five mRNAs were downregulated in LUAD, and their expression levels were positively correlated with those of RAMP2-AS1. CD44, CCND3, NCALD and MACF1 were selected as key mRNAs in LUAD based on prognostic analyses. Furthermore, functional enrichment analyses were performed and an interaction network was constructed to reveal the functions of the RAMP2-AS1-associated ceRNA in LUAD. The results indicated that the functions were mainly enriched in generic transcription pathways, cyclin D-associated events in G 1 and epithelial stromal transformation. Reverse transcription-quantitative PCR assays revealed that RAMP2-AS1, CD44, CCND3, NCALD and MACF1 expression was lower in tumor tissues than in normal tissues, while miR-296-5p expression was higher in tumor tissues compared with in normal tissues. The association between RAMP2-AS1 and MACF1 was further confirmed using in vitro experiments. Overall, the present results indicated that RAMP2-AS1, miR-296-5p, CD44, CCND3, NCALD and MACF1 may be involved in LUAD progression and may therefore serve as potential biomarkers and provide a theoretical basis for the study of the pathogenesis of LUAD.