Expression Of Survivin In Gastric Carcinoma And Analysis Of Its Correlation With COX-2 In Tumorigenesis

It has been demonstrated that tumorigenesis and its development is associated with concomitance of multifactors in longterm. Also theprogress of tumorigenesis is regarded as sophisticated multi-stages biologically, activation of oncogenes and inactivation of tumor suppressor genes disturb the normal regulation of the cell proliferation and differentiation, which leads to hyperplasia and poor differentiation of cells. Tumorigenesis is not only related to the growing speed of cells, but also to the mortality speed of cells according recent researches. The defect or block of apoptosis is also an important factor that results in the occurrence and development of tumor. So cancer is the disease of abnormal proliferation and differentiation of cells, and the disease of abnormal apoptosis.Gastric cancer are one of the most common malignancies in Chinese population with its low early diagnosis rates ,The great challenge confronting us is its resistance to chemotherapy and radiotherapy in advanced stage. Many changes in molecular events including oncogenes ,growth factors, cyclins, tumor suppressor genes, cell adhesion molecules and unstability of genes are involved in the development and progression of gastric cancer.But cell proliferation and apoptosis constitutes the elementary process of tumorigenesis.As the new member of Inhibitor of Apoptosis Protein(IAP) gene family,Survivin gene not only has characteristic of inhibiting apoptosis and promoting proliferation in tumor cells,But also increasing resistance to chemotherapy.The expression of survivin gene in tissues of stomach neoplasma and precancerous lesion are rarely reported,Cyclooxygenase-2 gene has the same roles as that of survivin gene,But the correlation of these two genes in tumorigenesis still remains unclear. Objective The purpose of study was to explore the expression of survivin gene in gastric cancer and chronic gastritis tissues.The expression of survivin was also detected in gastric carcinoma MGC-803 cell line.With analysis of the relationships between the expression of survivin and degrees of differentiation,lymph node metastases and TNM stages. To investigate its possible mechanisms in the development and progression of gastric cancer. Aiming to find an ideal tumor marker for diagnosis and prognosis.At the same time the correlation of expression of survivin and COX-2 was studied, In order to explore the co-regulation in the aspect of apoptosis of stomach cancer cells. Methods:1) Forty-five gastric cancer samples confirmed with histopathology were obtained from upper gastrointestinal endoscopy or surgery operation.Thirty chronic gastritis samples including ten specimens of trophic gastritis with atypical hyperplasia were also obtained. The mRNA expression levels of survivin were assessed by semi-quantity RT-PCR in these samples and gastric carcinoma MGC-803 cell line.2) Apoptosis index(AI, percentage of apoptosis cells) in gastric carcinoma was examined by flow cytometry.3) in 93 stomach carcinoma tissures and 20 normal gastric tissures , the expression of survivin and COX-2 were examined by using streptavidin-biotin peroxidase(SP) method.All of the tissues were fixed in 10% neutral formalin and enbedded in paraffin collected from 1999 to 2002.The correlation between these two genes was analyzed.Result:1, Results from RT-PCR:1.1 In 45 gastric cancer tissues,the rate of positive expression of survivin gene was 68.9% (31/45). In contrast, tissues of superficial gastritis and trophic gastritis with atypical hyperplasia did not express survivin. The discrepancy was significance statistically(P<0.01).The apoptosis index(AI) in positive expression of survivin was 1.12 ?0.92,Which is lower than that of negative group,There was a statistical significance in values of AI between two groups. 1.2 Divide the expression rates using gastric cancer cell differentiation, The expression rate of survivin in moderately differentiated and well-differentiated carcinoma was 50% by comparison to 81.5% in tha...