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 over-expression 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.