Identification Of Plasma MiRNA-21 As A Biomarker For Early Detection And Chemosensitivity Of Non-small Cell Lung Caner

ObjectiveThis study was to investigate whether plasma miRNA-21 ( miR-21 ) can be used as a biomarker for the early detection of non-small cell lung cancer (NSCLC) and to explore its association with clinicopathologic features and sensitivity to platinum-based chemotherapy.Methods1. Peripheral blood specimens from 63 patients with confirmed NSCLC were collected between October 2009 and August 2010 from the departments of Thoracic Surgery and Oncology in the First Affiliated Hospital of Nanjing Medical University. 13 paired pre- and post-chemotherapy plasma samples were collected from post-operative patients. 30 age- and sex-matched healthy volunteers as controls were collected from medical examination center.2. We used real-time quantitative RT-PCR to investigate the expression of miR-21 in the plasma of NSCLC patients and healthy controls.3. We used real-time quantitative RT-PCR to investigate the expression of miR-21 in the plasma of 13 post-chemotherapy samples compared with the levels in pre-chemotherapy samples.4. We used real-time quantitative RT-PCR to compared plasma miR-21 between PR(n = 11) samples and (PD + SD) (n = 24) samples.Results1. qRT-PCR analysis indicated that the NSCLC patients had significant higher levels of miR-21 in their plasma than in the controls (P < 0.0001).2. Plasma miR-21 expression was not related to age, sex, smoking status, pathologic type, lymph node metastasis and distant metastasis(P = 0.8798, P = 0.6426, P = 0.3344, P = 0.2170, P = 0.4491 and P = 0.0980, respectively).3. Plasma miR-21 was related to TNM stage (P < 0.001), plasma miR-21 expression was higher in stage T1-2 and in stage I-II patients (P = 0.0014, P = 0.0042).4. This marker yielded a receiver operating characteristic (ROC) curve area of 0.775 (95% CI: 0.681 - 0.868) with 76.19% sensitivity and 70.0% specificity.5. MiR-21 levels were significantly reduced in 13 post-chemotherapy samples compared with the levels in pre-chemotherapy samples(P = 0.0479).6. The levels of plasma miR-21 in PR samples were several folds lower than that of (PD + SD) samples (P = 0.0487).ConclusionPlasma miR-21 can serve as a circulating tumor biomarker for the early diagnosis of NSCLC and is related to the sensitivity to platinum-based chemotherapy.