Correlation of microRNA-335 expression level with clinical significance and prognosis in non-small cell lung cancer

Although treatments have improved significantly in recent years, the prognosis of patients with non-small cell lung cancer (NSCLC) remains poor. miR-335 has been demonstrated to play the antitumor role in several cancer types. Its expression was reduced in NSCLC tissues relative to noncancerous adjacent tissues. Furthermore, downregulation of miR-335 in A459 lung cancer cells promoted cell proliferation. In the present study, we aimed to investigate the clinical significance and prognostic value of miR-335 in NSCLC. The lung cancer tissues and adjacent nontumor lung tissues were obtained from 131 patients who underwent the primary surgical resection at Lianyungang First People's Hospital. Student t test was used to distinguish differences between groups. χ(2) test was involved for analysis of clinicopathological data. The overall survival was analyzed by the Kaplan-Meier method and the log rank test. Multiple Cox proportional hazards regression analysis was carried out to identify the independent factors that had a significant impact on patient survival. miR-335 was significantly lower in NSCLC samples compared to non-cancerous samples (P < .001). The expression level of miR-335 was significantly correlated with tumor histology (P = .028), lymph node metastasis (P = .002), differentiation degree (P < .001), and pathological TNM stage (P < .001). The log-rank test indicated that patients with decreased miR-335 expression experienced poor overall survival in NSCLC (P = .029). The results of the present study indicated that miR-335 was down-expressed in NSCLC, and is associated with tumor progression and poor prognosis, suggesting that the expression of miR-335 might be an independent prognostic factor of overall survival in patients with NSCLC.