Empirical Study For Screening Of TNM Stage Marker Genes Of Pulmonary Adenocarcinoma By Genomewide Expression Micoarray

Background:Lung cancer is the leading causes of cancer worldwide. The main component of it is non-small cell lung cancer (NSCLC)(80%), and lung Adenocarcinoma is the most important pathohistology type of NSCLC. Although after resection, The treatment to patients with lung cancer has been enhanced (as adjuvant therapy) and Some more effective therapy used for inhibiting metastasis (such as molecular targeted therapy), but the cure rate of lung cancer remains low. As other solid tumors, lung cancer were formed after long-term genetic heredity and changes of time. Identify new prognostic markers, new predictive markers, or developing new detection tools is one of the main areas of lung cancer research. However, the mobility of lung cancer is a multi-factor and complicated process which characterized by genetic heterogeneity, so detected only one or a few genes is not enough, the whole genome analysis will be more effective to demonstrate the complexity of lung cancer. In recent years, with the advantages of gene chip technology of high-throughput parallel detection of the genome, we can study the gene expression spectrum of the desired tissue and cells within the whole genome which provides a powerful tool for the study of tumor development and progression of multiple gene changes in the molecular mechanism. Thus, it has a special advantage in the research of molecular classification of lung cancer.Object:By comparing the surgical tissue gene expression of different TNM staging of lung cancer, Filter and select the marker genes from each TNM staging of lung adenocarcinoma; Validation the genes which shows significant difference in the mRNA level using RT-PCR, analysis the contact with the corresponding clinical pathological factors and the meaning as a molecular type related genes of lung cancer.Method:Using the Oligo chip with 25,100 individual genes, compared 10 cases of gene expression profiles between cancer tissues and paraneoplastic tissue without chemotherapy and radiotherapy in patients and selected the genes which has tend of express two times common differences. Then, analyzed the differentially expressed genes in different TNM stages (Ⅰ, 3 cases,ⅡandⅢA of 3 cases of 4 patients) using SAM software form those genes acquired from last step and to analyze the function of the differential genes using GoMiner software. KEGG software and semi-quantitative RT-PCR were for the analysis of the differential gene circuit and validation on the clinical cases.Result:1. comparison of gene expression profiles between cancer tissues and paraneoplastic tissue in ten patients, 640 genes were found in 10 samples was 2 more times differentially expressed, of which 289 genes up regulated in cancer tissue, 351 genes were down.2. Then we divided cancer into stageⅠ,Ⅱ,ⅢA, and screened genes express differences at different levels in various stages from the 640 differentially expressed genes. The result showed total of 16 genes, of which two genes were down-regulated, 14 were up-regulated. Seven genes in stageⅠshowed significantly differentia; 4 genes in phaseⅡshowed significantly differentia; 4 genes expressed differentially both in PhaseⅡandⅢA. In addition, we first found seven genes which were MIF1IP, CENPN, CBFA2T2, ANKRD36B, GINS2, ZMIZ2, LDLR differentially expressed in lung adenocarcinoma, suggesting MIF1IP, CENPN, ANKRD36B, GINS2 may be associated with lung cancer metastasis.3. Searching the function of 16 genes differentially expressed using GoMiner, of which two were related to cell signal transduction, three were related to growth, metabolism of cell, and four genes were transcription factor. The pathway 16 differentially expressed genes were analyzed using KEGG and obtained five-related pathway: MAPK signaling pathway (P = 0.006), B cell receptor signaling pathway (P = 0.032), colorectal cancer pathway (P = 0.036). T cell receptor signaling pathway (P = 0.043), Toll-like receptor signaling pathway (P = 0.046). In this study we found that differentially expressed genes in different TNM stages, or by participating in MAPK signaling pathway regulating the activity of enzymes to inhibit or promote the growth of tumor and Once again prove that mitogen-activated protein kinase (MAPK) signal transduction pathway has an important relationship with the occurrence, invasion and metastasis of cancerous cell which will become a new target of cancer therapy.4. The results of clinical verify differentially expressed genes MMP12: RT-PCR showed there was no MMP-12 mRNA expression in paraneoplastic tissue and was expressed different levels in cancers from stageⅠandⅡ,ⅢA, the mean of semi-quantitative was 0.551±0.140 and the summation was (1.082±0.424), Statistics showed the difference was significant (P = 0.001); Western blot results demonstrated that there was no MMP-12 protein expression in paraneoplastic tissue, while it has a low expression in cancer tissue of stageⅠand a high expression in stageⅡ,Ⅲ.Conclusion:Through screening of differentially expressed genes of lung adenocacinoma in different TNM stage, suggesting that predict significantly differential expressed genes in stageⅠof lung adenocacinoma could help early diagnosis of it. The significant differential genes expression in stageⅡ,ⅢA may associated with metastasis of lung adenocacinoma which is a potential prognostic biomarkers and new targets for drug therapy. We could monitor the development trends of disease by detecting changes in differentially expressed genes spectrum and Finally make treatment plan and estimate the prognosis.