Prognostic significance of serum miR-17-5p in lung cancer.

miR-17-5p is abnormally expressed in various tumor types. The aim of this study was to investigate the expression level of miR-17-5p in serum of patients with lung cancer and to determine whether serum miR-17-5p expression is related to the prognosis of patients with lung cancer. RT-qPCR was used to examine expression of miRNA-17-5p in 20 pairs of lung cancer and adjacent normal tissues, and sera from 221 patients with lung cancer and 54 matched controls. The correlation of serum miR-17-5p with clinicopathological factors or prognosis of patients with lung cancer was analyzed. The expression level of miR-17-5p obviously increased in lung cancer tissues (P = 0.004). Furthermore, serum miR-17-5p expression also significantly increased in patients with lung cancer compared with healthy individuals (P = 0.03). The survival analysis showed that serum miR-17-5p expression was closely related to the survival of patients with lung cancer. Patients with high miR-17-5p expression had shorter survival times [hazard ratio (HR) = 1.767, 95 %CI 1.039-3.005, P = 0.035]. A lower expression level of serum miR-17-5p helps extend the survival of patients with lung cancer. Thus, miR-17-5p may be potential biomarker for prediction the prognosis in patients with lung cancer.