Circulating microRNA-339-5p and-21 in plasma as an early detection predictors of lung adenocarcinoma

Background: Many studies have shown that differentially expressed miRs in body fluids can serve as biomarkers in non-invasive detection of the cancers. However, the clinical significance of plasma miRs in the diagnosis of lung adenocarcinoma (LA) is still not clear. Therefore, we examined the LA-specific miRs in plasma, which could be utilized to diagnosis and monitor LA in routine clinical practice. Methods: Twenty-eight LA cases and twenty-eight healthy controls were recruited to our study. MiRs differential expression in plasma was measured by miRNA Microarray assay and revalidated by using qRT-PCR based absolute quantification methods The diagnostic power of circulating miRs in LA was evaluated using the receiver operating characteristics (ROC) curves and the area under the ROC curves (AUC). Results: Tumor tissues and plasma levels of miR-339-5p were significantly down-regulated in LA patients compared with those in the control group, whereas the levels of miR-21 in LA patients were significantly higher than control group. ROC analysis showed that miR-339-5p and miR-21 could distinguish LA patients from healthy controls with high AUC (0.900 and 0.880, respectively), sensitivity (0.821 and 0.821, respectively) and specificity (0.929 and 0.964, respectively). Importantly, the combination of miR-339-5p and miR-21 markedly improved AUC (0.963), sensitivity (0.929) and specificity (0.929). Conclusion: Plasma miR-339-5p or miR-21 could serve as a potential biomarker for diagnosis of LA, however, the combination of miR-339-5p and miR-21 was more efficient for LA detection.