Background: Development of noninvasive biomarkers could potentially contribute to extending the 5-year overall survival rate of nonsmall cell lung cancer (NSCLC) patients. Circulating microRNAs (miRNAs), due to their high stability, have the potential to become valuable cancer biomarkers. Methods: Using reverse transcription-quantitative polymerase chain reaction and testing three methods for data normalization, the expression levels of six miRNAs were evaluated in serum samples obtained from 50 NSCLC patients. Subsequently, the clinical significance of the tested miRNAs was determined. Results: Significant downregulation of miR-21-5p, miR-30a-5p, and miR-126-3p and upregulation of miR-210-3p and miR-486-5p in serum samples of NSCLC patients were identified in comparison to healthy controls. miR-205-5p appeared to be undetectable in all tested samples. Furthermore, miR-210-3p was differentially expressed between two subtypes of NSCLC. Receiver operating characteristic analysis for miR-210-3p revealed the area under the curve of 0.842 (95% confidence interval, 0.72-0.96; p = 0.0003) and demonstrated that miR-210-3p displayed considerable accuracy in discriminating between lung adenocarcinoma (AC) patients and healthy controls. Conclusions: Findings from this preliminary study indicate that five of six tested miRNAs were deregulated in the serum of NSCLC patients. Moreover, miR-210-3p appears to be a promising biomarker for diagnosis of lung AC.
Keywords: biomarker; diagnosis; lung adenocarcinoma; miR-210-3p; microRNA; nonsmall cell lung cancer.