Detection of lung cancer with blood microRNA-21 expression levels in Chinese population

The analysis of molecular markers in the biological field has been proposed as a useful tool for cancer diagnosis. MicroRNAs (miRNAs) may regulate diverse biological processes and play a significant role in tumorigenesis. The potential use of blood-based miRNAs as a biomarker of cancer and as a target for therapeutics is promising. The purpose of this study was to determine whether aberrant miRNA expression can be used as a molecular marker in peripheral blood for the diagnosis of lung cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to analyze the expression levels of mature microRNA-21 (miR-21). Blood samples from 20 lung cancer patients and 10 healthy individuals were collected. The data were compared for the diagnosis of lung cancer. The results demonstrated that miR-21 was present in the peripheral blood in a markedly stable form and could be detected by real-time PCR sensitively and specifically. A significant difference was observed between the lung cancer cases and controls regarding miR-21 levels in peripheral blood (1947.26 +/- 930.56 pg/ml vs. 943.42 +/- 314.12 pg/ml, P=0.005). Furthermore, the overexpression of miR-21 showed a highly discriminative receiver operating characteristic (ROC) curve profile, clearly distinguishing cancer patients from cancer-free subjects with an area under the ROC curve (AUROC) of 0.912 +/- 0.045. The detection of miR-21 expression yielded 78.80% sensitivity and 100.00% specificity in the diagnosis of lung cancer. These findings indicate that in peripheral blood miR-21 may serve as a potential molecular marker for lung cancer and provide a new approach in the diagnosis of lung cancer.