| Background and objectives: Gastric cancer is one of the most common malignant tumors in the world, which is also the major cause of carcinoma death. The tumorigenesis of gastric cancer is a serially dynamic process concerned of the activation of many oncogenes, inactivation of anti-oncogenes and the subsequent changes of cytobiological behaviors. Lots of oncogenes and anti-oncogenes play different roles in different biochemical pathways. They communicate to interact each other to regulate the occurrence and development of tumor. As other tumors, the mechanism of gastric carcinogensis has not been clear. Recent studies showed that nuclear factor-KB (NF-k B), as an important nuclear factor, regulates the expression of many genes. It plays important roles in immune reaction, inflammatory reaction, cell apoptosis, carcinogensis. Cyclooxygenase-2(COX-2) and inducible nitric oxide synthase(iNOS) are two inducible enzymes, which are strongly expressed when they suffer from different stimulus, such as growth factors, inflammatory factors, lipopolysaccharide(LPS), oncogenes. COX-2, iNOS and NF-kB are strongly correlated to the progression and aggressiveness of carcinomas. In order to investigate the possible mechanism of gastric carcinoma, an immunohistochemical Sabc (Strept Avidin Biotin Complex) method was used to examine the expression of above three kinds of proteins. This study evaluated the roles of COX-2, iNOS and NF-kB in occurrence , development , invasion and metastasis of gastric carcinoma as well as their interaction in order to guide the early dignosis or judge prognosis of gastric carcinoma and provide theoretical foundation for prevention and clinical treatment.Materials and Methods: (1) 53 cases of surgically resected gastric cancer(GC) tissue samples , 70 cases of various gastric changes tissue specimens underwent endoscopy were collected(28 chronic superficial gastritis, 23 chronic atrophic gastritis with intestinal metaplasia, 19 dysplasia). All the tissues were fixed in 10% neutral formalin and embedden in paraffin. They were all confirmed pathologically. The group of chronic superficial gastritis(CSG) was considered as a control group. (2) Sabc immunohistochemistry technique was used to detect the expression of COX-2 and iNOS and NF-KBp65 proteins in chronic superficial gastritis(CSG), chronic atrophic gastritis with intestinal metaplasia(CAG+IM), dysplasia(Dys) and gastric cancer(GC) tissues. Staining results were evaluated by semi-quantity analysis, which associated with staining intensity and the number of positive cells. (3) The data was analysized by statistical software SPSS12.0. x2-test and Spearman correlation were used to compare the difference between groups, a =0.05 was considered as statistically significant value.Results: 1.(1) The positive staining of COX-2 is mainly located in cytoplasm. There was strongly positive staining in body of gland cells of GC, partly in interstitial cells and smooth muscle cells. There was moderately positive staining in CAG+IM and Dys tissues. Interestingly, positive staining in body of gland cells of CSG were less than in inflammatory cells. (2) In CSG, CAG+IM, Dys and GC, the positive rates of COX-2 were 17.86%(5/28), 30.43%(7/23), 42.11%(8/19), 62.26%(33/53), respectively. There were significant differences (P<0.05) when gastric carcinoma group compared with CSG, CAG+IM separately. There were no significant differences(P>0.05) when the other groups were compared with each other. (3) In the better-differentiated group, worse-differentiated group ,the positive rates of COX-2 were 72.97% (27/37) , 37.50% (6/16), respectively. There were significant differences (P<0.05)when the expression of COX-2 of above two groups were compared with each other in gastric carcinoma. Of 53 cases gastric carcinoma ,in the group without serose infiltration and the group with serosa infiltration, the positive rates of COX-2 were 38.46% (5/13) , 70.00% (28/40) , respectively. There were significant differences (P<0.05) betwe...
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