Low Expression Of Let-7 With Poor Prognosis And High Expression Of HMGA2 With The Occurrence And Development Of Lung Cancer:A Meta-analysis

Background and objective :Lung cancer is one of the common malignant tumor, in the world the incidence and mortality are in the rapid uptrend. In recent years, it become the highest incidence of all the tumors and has serious threat to health and life of human.The gold standard for diagnosis of lung cancer is the pathology, therefore, the majority of lung cancer is diagnosed at the advanced stage. Although, some of the tumor markers could improve the early diagnostic rate and prompt prognosis of lung cancer, low specificity lead to much uncertainty in clinical application, which greatly reduce the survival rate of patients. The early diagnosis and analysis of accurate prognosis are the key points to improve the survival rate of patients with lung cancer. Therefore, it is important to find some specific tumor markers which could improve the early diagnosis and analysis of accurate prognosis. The discovery of micro RNAs has opened up a new thought for predicting the prognosis of lung cancer. Many studies have found that some micro RNAs can prompt the prognosis of lung cancer, but their prognostic value is still controversial. Recently studies have found that the expression of HMGA2 in lung cancers tissues is higher than that in normal lung tissues. HMGA2 is closely related to the occurrence and development of lung cancer. Some studies have found that the let-7 can suppress HMGA2 expression specifically, and targeting to HMGA2 is better than that to the RAS.HMGA2 may become a new target of diagnosis and treatment of lung cancer. At present, studies of the low expression of let-7 about prognosis, expression and significance of HMGA2 in lung cancer have been reported in the literature both indomestic and foreign, however, the results are not consistent. To evaluate the prognostic role of micro RNA let-7 and the clinical significance of HMGA2 in lung cancer, we systematically reviewd and synthesized the literature by meta-analysis approach.Methods:Studies about low expression of let-7 correlation with prognosis of lung cancer and expression of HMGA2 correlation with occurrence and development of lung cancer were identified by searching Pub Med, web of science, medline, cochrane library, Google scholar, CNKI, CBM, VIP database since the date of establishing database. The languages were limited to Chinese and English, the keywords were“lung cancer, non-small cell lung cancer, small cell lung cancer, lung adenocarcinoma, lung squamous carcinoma, NSCLC, SCLC, let-7, micro RNAs and prognosis”and “non-small cell lung cancer, lung adenocarcinoma, lung squamous carcinoma, NSCLC, HMGA2, HMGI-C, high moblity group A2”. We evaluated the quality of the articles accordance with the inclusive criteria and extract the relevant datas. By using Stata SE12.0 software, heterogeneity among combined studies was assessed, the pooled hazard ratio(HR) with their corresponding 95% confidence intervals(CIs) and odds ratios(OR) with their corresponding 95% confidence intervals(CIs) were calculated.Results:1. Eventually, 10 studies of the low expression of let-7 correction with prognosis of lung cancer were used for this meta-analysis. Results show that: the low expression of let-7 indicates a poor overall survival rate, hazard ratio with a value of 1.55(95%CI:1.16-2.09, p<0.05).2. Eventually, 9 case-control studies of occurrence and development of HMGA2 in NSCLC were used for this meta-analysis. Results show that: the expression of HMGA2 in lung cancer is significantly higher than paraneoplastic normal tissue. High expression of HMAG2 has been observed in the patients with late TNM stage, especially in the patients with lymph node metastasis. There is nostatistically significance with pathological classification, gender, degree of differentiation, tumor size, smoking status.Conclusion:1.Low expression of micro RNA let-7 is closely related to the poor prognosis of lung cancer. Let-7 as prognostic tumor market is expected.2. Higher positive expression of HMGA2 in the lung tissues is possitively correlated with occurance of lung cancer and late TNM stages. Thus, HMGA2 may become a new tumor marker of early diagnosis of lung cancer, a new means to judge the lung cancer biology behavior.HMGA2 may be used in genetic therapy of lung cancer as a new target in the future.