RESUMO
OBJECTIVE: To investigate the difference of the expression pattern of tumor-associated antigen MG(7)-Ag in gastric carcinoma between Hans and Tibetans. METHODS: Avidin-biotin peroxidase complex immunohistochemical methods were adapted to examine the expression pattern of MG(7)-Ag in 200 patients with gastric carcinoma, including 100 Tibetan patients and 100 Hans patients, 10 patients with chronic artrophic gastritis, 18 with gastric mucosal dysphasia and 10 subjects with normal gastric mucosa served as control. RESULTS: The positive rate for MG(7)-Ag was 92.4% and 88.7% in Tibetan and Han gastric carcinoma patients, 55.6% and 38.9% in Tibetan and Han gastric mucosal dysplasia patients, 20.0% and 10.0% in Tibetan and Han chronic atrophic gastritis patients, respectively. There was no positive expression in normal gastric mucosa of both Hans and Tibetans. >From normal gastric mucosa, chronic artrophic gastritis and gastric mucosal dysplasia to gastric carcinoma, expression of MG(7)-Ag showed an ascending tendency in the same group of subjects or patients (P < 0.01). However between Hans and Tibetans there was no significantly different expression of MG(7)-Ag. In gastric carcinoma, the expression pattern of MG(7)-Ag was not related to tumor cell differentiation and metastasis of lymph nodes in Hans and Tibetans (P > 0.05), but in the same group the expression of MG(7)-Ag was related to metastasis of lymph nodes. CONCLUSIONS: The expression pattern of MG(7)-Ag displayed no significant difference between Hans and Tibetans, The tumor associated antigen MG(7)-Ag in gastric carcinoma can be used in Tibetans as a reliable marker to predict early gastric cancer.