Decreased circulating miR-375: a potential biomarker for patients with non-small-cell lung cancer.

Abstract MicroRNAs (miRNAs) are directly involved in cancer initiation, progression and metastasis. Alterations of miRNAs expression in cancer tissue may be reflected in circulation. We attempted to investigate the expression and clinical significance of plasma miR-20a, miR-31 and miR-375 in patients with non-small cell lung cancer (NSCLC). The plasma levels of miR-20a, miR-31 and miR-375 in 164 NSCLC patients and 164 healthy controls (discovery cohort) were evaluated and compared among various clinicopathological characteristics. The relationship between miRNA expression and clinical outcome of NSCLC patients was examined in an independent cohort (53 cases and 53 controls). The expression level of miR-375 in tissue was also examined. Plasma miR-375 levels in NSCLC patients were significantly decreased in both patient cohorts ( P P P  = 0.029). This association was independently validated in a separate cohort of 53 NSCLC patients (HR = 2.406, 95% CI 1.170–4.945, P  = 0.017). The expression level of miR-375 was also found to be significantly down-regulated in NSCLC tissues compared with paracancerous tissues ( P