Diagnostic p53 expression in gastric endoscopic mucosal resection

Endoscopic mucosal resection (EMR) has been standardized for the treatment of intestinal type of intramucosal gastric carcinomas, and careful histolog ical examination of the resected specimen is important for further treatmen t, To evaluate the diagnostic utility of p53 expression in gastric EMR samp les, using immunohistochemical staining, we examined 24 gastric carcinomas (22 intestinal types and two diffuse types) and 20 adenomas removed by EMR, Intestinal type of adenocarcinomas revealed strong p53 expression in 13 ca ses (59%), weak in four cases (18%), and negative in five cases (23%), Rese ction margins of 11 carcinomas were involved in the carcinoma cells, which showed the same p53 expression pattern with main carcinoma cells. Squeezed carcinoma cells, remaining in resection margins, were definitely identified by strong p53 expression in seven cases of which the main tumor strongly e xpressed p53. Microscopic in situ carcinoma could be easily detected in p53 immunostaining. Multifocal involvement and submucosal invasion of carcinom as could be demarcated easily and definitely by strong p53 expression of ca rcinoma cells. All adenomas showed diffuse weak p53 expression. The differe nce of p53 expression (p<0.001) could be used as a differential diagnosis b etween adenomas and carcinomas. According to these results, we propose that for careful histological examination in hospital diagnosis, both histologi cal evaluation and p53 immunostaining are important diagnostic parameters i n EMR samples of the intestinal type of gastric carcinomas.