Analysis of p53 expression in precancerous and malignant gastric mucosa.

P53 overexpression, detected by immunohistochemical analysis, has been reported in about 50% of gastric cancers whereas scarce data are available on the p53 oncoprotein in precancerous gastric lesions. This study focused on the p53 expression in gastric cancerous and precancerous lesions. One hundred gastric specimens obtained during endoscopy were analyzed: 14 cases of normal gastric mucosa, 53 of chronic gastritis with intestinal metaplasia and/or dysplasia and 33 gastric tumors. An immunoperoxidase technique and monoclonal anti-p53 antibodies were employed. Eleven out of 31 gastric carcinomas overexpressed p53. No correlation was observed between p53-positivity and histological type and grade of tumors. All precancerous lesions were p53-negative. Our results suggest that p53 overexpression is a relatively late event in gastric carcinogenesis.