Neuro-endocrine type of gastric carcinoma. Immunohistochemical and electron microscopic studies of 100 cases.

1,351 specimens resected surgically from 100 patients with gastric carcinoma were studied with PAP immunoperoxidase and ultrastructural method. The tumor cells were found positive for gastrin, serotonin, somatostatin and argyrophil particles in 19 patients. Among them the gastrin-secreting tumor cells consisted of 50% of the total in 4 cases, representing a separate new subtype, neuro-endocrine (NE) gastric carcinoma. Of the 100 cases, 16 (32%) contained NE cells among 50 undifferentiated type, while only 3 cases (6%) contained NE cells among the remaining 50 cases, the well-differentiated type. These results suggest that the appearance of NE tumor cells is closely correlated with the degree of differentiation of cancer, and confirms theoretically the heterogenicity of gastric carcinoma, and further supports the concept that exocrine and endocrine type gastric cancer cells are isogenous, i.e., from the endodermal stem cells.