RESUMO
Dysregulation in the miRNA-21 expression has been previously observed in a number of malignancies and not only in the tumor cell itself but also in the body fluids of the cancer patients. The present study aimed to find out the clinical significance of cell-free circulating miRNA-21 as an efficient non-invasive biomarker for the screening of lung cancer patients. The present case-control study included plasma samples from 80 lung cancer patients and 80 healthy controls. Magnetic bead technology was used for efficient miRNA isolation and advanced TaqMan miRNA assays were used for the quantification of miRNA-21 level in the plasma of the lung cancer patients and healthy individuals.The overall mean relative expression level of plasma miRNA-21 among lung cancer patients (2.32±1.7) was higher when compared to healthy individuals (0.715 ± 0.48) and it showed a significant difference of p<0.0001. The area under ROC curve was 0.8913 [95% confidence interval (CI): 0.8394 to 0.9431, p< 0.0001] and the sensitivity and specificity were both 80.0% when the cut-off value was 1.207. In conclusion, plasma miRNA-21 can be efficiently extracted by the magnetic bead technology and quantified by the advanced TaqMan miRNA assay. Plasma miRNA-21 showed a high ability to distinguish between lung cancer patients and healthy individuals, therefore can be used as an efficient non-invasive biomarker for the screening of Lung cancer patients.