| ObjectiveThe mortality of gastric cancer is highest of malignant tumors in our country, so early diagnosis and early detection have great significance in prevention and treatment of gastric cancer . It's important to find valid screening methods with the purpose of decreasing mortality of gastric cancer. There are some new antigens in tumor cells which called tumor antigen and lacks of specific or differentiated antigens which represent poor differentiation of tumor cells. The appearance or disappearance of above antigens is important evidence for tumor diagnosis. The antibody MG7 is a monoclonal antibody and the antigen MG7 recognized by which is one of tumor - associated antigens. It was reported that there was no expression of antigen MG7 in normal gastric mucosa, low expression in other malignant tumors and high expression in gastric cancer , but its not clear whether it can be an useful index in diagnosis of gastric cancer. Pepsinogen C ( PGC ) is an inactive precu-sor of pepsin , a special functional enzyme of gastric mucosa. Human PG can be devided by two subgroups with different biochemistry and immuno competence:PGA and PGC. It was reported recently the level of serum PGA and PGA/PGC decreased in chronic atrophic gastritis and gastric cancer ,but it's unknown whether PGC can be used as a good negative marker for gastric cancer and precancerous disease.Whether antigen MG7 and PGC can be used as good indexes in diagnosis of gastric cancer, it needs to evaluate with diagnostic test. A good index in screening and early diagnosis are both high in sensitivity and specitivity. Sometimes single index cant satisfy the requests of two aspects, so many scholars used several indexes altogether . At present, there is no report on combining the two indexes of MG7 and PGC in diagnosis of gastric cancer.The infection of Helicobacter pylori is the direct cause of chronic activating gastritis and there is intimate relationship between H. pylori infection and gastric cancer and precursors of gastric cancer. So H. pylori has been named as first - class carcinogen. It was unclear how can H. pylori play roles in occurrence and development in gastric cancer. At present , there were few reports on the relationship between antigen MG7 or PGC with H. pylori infection . So the aim of this study is to;1. To investigate the dynamic expression of gastric cancer - associated antigen MG7 and pepsinogen C and their relationship with H. pylori infection in gastric cancer and precancerous diseases.2. To investigate the value of MG7 and PGC in early detection of gastric cancer and further to evaluate the value of combining the two indexes in diagnosis of gastric cancer.MethodsWe examined 336 cases of different gastric mucosal biopsy materials of third research department of cancer institute of china medical university . The biopsies came from gastric screening from the year 1997 ~2002 in zhuanghe region, of Liaoning Province, the region with high incidence of gastric cancer. The cases included 46 cases of nor-mal gastric mucosa, 55 cases of superficial gastritis,39 cases of gastric ucler or erosion, 68 cases of atrophic gastritis, 51 cases of dysplasia and 77 cases of gastric cancer. Among the 336 cases, there were 199 cases of male, 137 cases of female,average age 51 years. There was no significant different between the disease group and health control group in component of sex and age( p > 0. 05 ). All of the biopsies were i-dentified by pathology diagnosis. The two ?step SP method of immuno-histochemistry was used to examine the expression of MG7 and pepsin-ogen C in 336 cases of stomach mucosa; the H. pylori infection was determined by HE stain, PCR and ELISA.Results1. The positive rate of MG7 expression in 46 cases of normal gastric mucosa was 0 percent and the PGCs was 100 percent. The positive rates of MG7 expression in superficial gastritis/ gastric ulcer or erosion , atrophic gastritis or gastric dysplasia and gastric cancer were increased significantly on sequence ( P < 0. 05 ) and the expr...
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