To Investigate The Expression Of Hnrnp A2/b1 In Nsclc And The Role Of Hnrnp A2/b1 In The Pathogenesis Of Nsclc

ObjectiveTo study the expression of heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) in Non-small cell lung cancer (NSCLC), and the interaction between hnRNP A2/B1 protein and mRNA of DNA repair enzymes: O6-methylguanine DNA-methyltransferase (MGMT),8-oxoguanine DNA glycosylase (OGG1),redox factor 1(ref-1),DNA-dependent protein kinase (including DNA-PKcs and ku) and to detect the role of hnRNP A2/B1 in the pathogenesis of NSCLC. To investigate the value of hnRNP A2/B1 expression in sputum for early diagnosis of NSCLC and in identifying the adenocarcinoma cells in pleural effusions.MethodsThe expression and distribution of hnRNP A2/B1 were detected by immunohistochemistry and Western Blot on 50 NSCLC samples from patients who underwent resection in Zhongshan Hospital. And hnRNP A2/B1 mRNA expressions were tested by real-time PCR. Co-immunoprecipitation (Co-IP) combined RT-PCR were used to investigate whether hnRNP A2/B1 could be bounded with the mRNA of the mentioned 5 DNA repair enzymes in human lung cancer cell line (HTB-182). Then immunohistochemistry and real-time PCR were used to detect the expression of MGMT in the same group of NSCLC patients.63 sputum specimens of patients who were suspected as lung cancer were collected to compare the regular examination of sputum cells with detection of hnRNP A2/B1 by immunohistochemical staining method. In addition,100 effusion specimen were assessed by immunohistochemical analysis in cell blocks. SPSS 13.0 was used as statistics tool.ResultsHnRNP A2/B1 protein and mRNA expressions were increased in the tumor tissues of NSCLC than that in the corresponding normal lung tissues. HnRNP A2/B1 was expressed predominantly in nuclei of tumor cells. The positive rate and immunohistochemistry score of hnRNP A2/B1 in tumor tissue were significantly higher than that in normal tissue (p＜0.01). In stageⅢ-ⅣNSCLC, hnRNP A2/B1 expression was higher than that in stageⅠ-Ⅱ. There was no difference of hnRNP A2/B1 expression in different age, sex, histological type, and smoking history. The result of Co-IP combined RT-PCR suggested hnRNP A2/B1 was bounded with MGMT mRNA. And MGMT expression was decreased in tumor tissue of NSCLC. Besides, the sensitivity and specificity of regular examination of sputum cells were 31.8%and 100%, while the detection of hnRNP A2/B1 by immunohistochemical staining method were 80%and 68.4%. The detection of hnRNP A2/B1 was more effective by immunohistochemical staining method in diagnosis of lung cancer. In addition, the sensitivity rate of hnRNP A2/B1 in identifying the adenocarcinoma cells in pleural effusions was 100%and the specificity rate was 70%.ConclusionOur study showed that hnRNP A2/B1 protein and mRNA were highly expressed in NSCLC, and hnRNP A2/B1 was bounded with MGMT mRNA, which indicated that it might be one of the mechanism of hnRNP A2/B1 participating in the pathogenesis of NSCLC. The sensitivity of detecting hnRNP A2/B1 in the sputum was obviously higher than the regular examination of sputum cells. It was valuable in early diagnosis of lung cancer. Combining this method with regular test, it would be more efficient. And detection of hnRNPA2/Bl is an accessory method for differentiation between adenocarcinoma and mesothelial cells.