[Immunohistochemical and ultrastructural study on neoplastic endocrine cells and Paneth's cells in gastric carcinoma]

One hundred and twenty-eight cases of gastric carcinoma were examined with immunohistochemical technic for carcinoembryonic antigen (CEA), human chorionic gonadotropin (HCG), serotonin, gastrin and lysozyme. CEA were observed in 105 cases. Twenty-four cases were positive for HCG, 53 cases for serotonin, 31 cases for gastrin, 89 cases for lysozyme. Sixty-nine cases exhibited more than two hormones or one hormone and lysozyme simultaneously in different cells of the same tumor. Ultrastructurally, sometimes three types of secretory granules were noticed. The electron dense granules in the lysozyme-containing tumor cells were similar to those of Paneth's cells in intestinal metaplasia. The positive rates of the above three hormones, lysozyme and multi-marker expression in diffuse type carcinoma were higher than those in intestinal type, and 42/44 cases of the diffuse type carcinoma were histologically undifferentiated carcinomas or signet-ring cell carcinomas. Lymph node metastasis occurred more frequently in those carcinomas with hormone or lysozyme positivity. These findings suggest that these neoplastic endocrine cells and Paneth's cells have originated from multipotential differentiation of neoplastic stem cells in the stomach, reflecting the state of the gene activity in the tumor cells.