Study On Gene Expression Patterns Of Low-differentiated Human Lung Adenocarcinoma At Stage Ⅰ And Clinical Significance Of Expression Status Of Cyclin D1, MMP-2 And PRb

Lung cancer is the most common malignant disease and its morbidity is the highest one among all kind of cancers in our country. It is a great threat to people's health and life, especially there is ascending trend of its morbidity. For these reasons, there is a great significance to have a deep study on etiology of the disease and methods of diagnosis, prophylaxis and treatment for it.Objectives: 1. To analyse the abnormal gene expression patterns of low-differentiated human lung adenocarcinoma at stage I and screen disease implicated genes with cDNA chip. 2. To observe status of proteins encoded by some of those abnormally expressed genes in lung cancer tissues using immunohistochemistry and to investigate the association of these proteins with both clinicopathologic parameters and clinical outcome in resected lung adenocarcinomas.Methods: The mRNA were extracted from cancer tissues and matched normal lung tissues of 3 cases with low-differentiated human lung adenocarcinoma at stage I . The cancerous mRNA was labeled by Cy5-dUTP, the control mRNA was labeled by Cy3-dUTP. Followed that, the labeled mRNA were hybridized to the cDNA chip of 8192 genes. The information was obtained by managing the cDNA chip with ScanArray4000 scanner and GenePixS.O software and by this way the expression profile of low-differentiated human lung adenocarcinoma at stage I was taken. Cyclin Dl, MMP-2 and Rb were selected for further study among those remarkable differently expressed genes. The proteinsencoded by these three genes were detected immunohistochemically in formalin-fixed and paraffin-embedded sections of 67 completely resected primary lung adenocarcinomas. The data about proteins expressing and clinicopathologic parameters such as size of primary tumor, metastasis of local lymph node, clinical stage, grade of tumor differentiation, survival time of post-operation and relapse/metastasis after operation were input to a computer. Relationships between immunohistochemical expressions of cyclin Dl, MMp-2 and the Rb gene product (pRb) and those clinicopathologic parameters were analyzed with SPSS10.0 software, respectively. Meanwhile the association of the immunohistochemical expressions of these proteins with the prognoses of 67 patients after a complete resection was investigated by the same software. The survival rate was calculated with Kaplan-Meier method, the different significance was verified with Log-Rank test, univariate analysis and multivariate analysis about influence on prognosis by implicated factors were used Cox model.Results: 1. There were 580 genes differentially expressed between cancer and normal lung tissue, and 405 (362 known and 43 unknown) were up-regulated while 175 (158 known and 17 unknown) were down-regulated. Among these genes, 66 were remarkable difference between two tissues, 39 (35 known and 4 unknown) were up-regulated and 27 (24 known and 3 unknown) down-regulated. We found that those known genes were involved in many different steps of cell living activities such as regulating speed of growth and transduction of information. Wefound decorin gene expression down-regulated in low-differentiated human lung adenocarcinoma firstly in our country. 2. To analyse the relationship of each detected protein versus each clinicopathologic parameter, the results we found as follows: (1). Overall, the positive expression rates of cyclin Dl, MMP-2 and pRb in all 67cases were 76.1%, 70.1% and 32.8%, respectively. (2). In groups based on primary tumor size, ^9cm2 or >9cm2, the positive expression rates of cyclin Dl were 73.7% and 79.3%, MMP-2 were 60.5% and 82.8%, pRb were 34.2% and 31.0%, respectively. Only MMP-2 expression had significant difference in two groups (by Chi-Square test). (3). For locale lymph node, in groups of with mediastinal lymph node metastasis, pulomonary hilar lymph node metastasis and without lymph node invasion, the positive expression rates of cyclin Dl were 90.9%, 79.2% and 68.8%, whereas MMP-2 were 100%, 95.8% and 40.6%, pRb were 18.2%, 25% and 43.8%, respectively. Onl...