Characteristics of gastric and intestinal mucin phenotypes of gastric carcinoma

Background/Aims: To better understand the carcinogenesis pathway in gastric cancer, we investigated the relationship between mucin phenotype and clinicophatologic features. Methodology: The study was conducted in 203 consecutive patients with newly diagnosed gastric cancer. Sections from representative paraffin blocks of each case were immunostained with human gastric mucin, MUC2, CD10, and paradoxical concanavalin A class III. Gastric cancers were divided into three phenotypes; gastric phenotype (G-type), intestinal phenotype (I-type), and the Null phenotype (N-type). Surrounding non-cancerous mucosa was also phenotyped as G- or I-type. Results: In G-type surrounding non-cancerous mucosa, I-type cancers were more frequent among the differentiated type gastric cancers whereas G-type cancers were more frequent among the undifferentiated type gastric cancers (p=0.004). As for surrounding non-cancerous mucosa, the G-type mucosa was more frequently seen than the I-type mucosa in incomplete intestinal metaplasia (p<0.001). I-type gastric cancers were more frequent in non-cancerous surrounding mucosa with incomplete intestinal metaplasia, and G-type cancers were more frequent in non-cancerous surrounding mucosa with no intestinal metaplasia (p=0.03). Conclusions: G-type gastric cancers may develop in G-type gastric mucosa with incomplete intestinal metaplasia and progress to the G-type undifferentiated carcinomas or the I-type differentiated carcinomas.