Significance of the Mucin Phenotype of Early Gastric Cancer

Background and Objectives:Histochemical studies have shown that differentiated gastric cancer(D-GC)can be classified according to the phenotype of expressed mucin.In the present study, we investigated the biological divergence of early stage D-GCs expressing different types of mucin. Methods:Specimens from 73 surgically resected early stage D-GCs were classified on the basis of the phenotype of expressed mucin and immunohistochemical staining for p53,c-erbB-2,and Ki67 protein. We also examined the relationship between the nature of adjacent mucosa and the mucin phenotype of D-GC. Results:Expression of p53 protein did not differ among the samples. C-erbB-2 was overexpressed in some D-GCs but not in those expressing gastric-type mucin. Although the ratio of Ki67-positive cancer cells was similar among D-GCs with different types of mucin,the distribution of these cells in cancer glands differed. In addition,we identified pure-type intestinal metaplasia in 11.8% of D-GCs expressing gastric-type mucin and in 46.5% of D-GCs expressing intestinal-type mucin. Conclusion:These findings suggest that biological properties and the nature of the gastric mucosa adjacent to the tumor differ between early stage D-GCs expressing gastric-type and those expressing intestinal-type mucin. (Jikeikai Med J 2003;50:29-36)