Objective The objective of this study was to investigate the miR-345 expression level in non-small cell lung cancer(NSCLC)tissue and its potential clinical significance.Methods Real-time PCR was conducted to evaluate the expression of miR-345 in NSCLC tissues in 98 samples and cell lines.Then the association between tissue miR-345 expression level and clinical outcomes was further analyzed.Results The expression level of miR-345 was significantly decreased in NSCLC tissues and cell lines when compared to the controls(P<0.05).miR-345 expression level in NSCLS tissues was associated with various clinicopathological parameters including LN metastasis(P<0.001),distant metastasis(P=0.028),TNM stage(P=0.004)and grade(P=0.011).In addition,the NSCLC patients in the low miR-345 expression group showed significantly shorter overall survival time than that in the high miR-345expression group(P=0.021).Multivariate analysis showed that the expression of miR-345 was an independent risk factor for NSCLC(HR=3.897,95% CI:2.263~10.440;P=0.012).Conclusion The expression level of miR-345 was decreased in NSCLC tissues as well as cell lines compared with normal controls.Low miR-345 expression in tissues was associated with progression and poor prognosis of NSCLC.These results indicate that miR-345 may be a novel prognostic marker in NSCLC.

Objective To investigate thymidylate synthase on pemetrexed treatment of lung adenocarcinoma effect relationship.Methods The 60 patients with lung adenocarcinoma in our hospital from January 2014 to January 2016 were selected as the research subjects.They were treated with pemetrexed.According to the clinical efficacy,they were divided into the effective group (n =27) and ineffective group (n =33) after 3 courses of treatment.The levels of thymidylate synthase (thymidylate synthase,TS),TS mRNA expression,and the expression of TS protein in the tumor tissues of two groups were analyzed by enzyme-linked immunoadsorbent assay (ELISA),fluorescence quantitative polymerase chain reaction (PCR),and immunohistochemistry.The relationship between TS level and pemetrexed in the treatment of lung adenocarcinoma was investigated.Results The level of ST in peripheral blood of the effective group was significantly lower than ineffective group.The objective response rate and protein of ST gene low expression were significantly higher than high expression of ST.Conclusions The level of thymidylate synthase in patients with adenocarcinoma of the lung is related to the therapeutic effect of pemetrexed in the treatment of adenocarcinoma of the lung.It can be used as a molecular marker to evaluate the clinical efficacy of pemetrexed in the treatment of patients with lung adenocarcinoma.