In thirty cases of resected primary gastric carcinoma, the relative utility of argyrophilic nucleolar organizer regions (AgNORs) staining (single staining) and sequential staining technique using proliferating cell nuclear antigen (PCNA) and AgNORs was studied. The mean number of AgNORs in PCNA-positive cells was significantly larger than that in AgNORs single stained cells. For above two groups, correrating mean number of AgNORs with clinicopathological factors revealed a significant difference between stage I + II and stage III + IV. In lymph node metastasis, the depth of invasion and size, only sequential stain-positive cells showed significant difference. On the other hand, only that of sequential stain-negative cells, a significant difference was found with regard to liver metastasis. As for other assessment, the ratio of AgNORs area per nuclear area was investigated using an image analyzer (IBAS 2000 KONTRON). Comparison of the ratio of AgNORs area per nuclear area between PCNA-positive cells and AgNORs single stained cells revealed a significant difference in regard to lymph node metastasis. On the other hand, between the ratio of AgNORs area per nuclear area in PCNA-negative cells and that of AgNORs single stained cells, a significant difference was found in regard to liver metastasis. Thus, the evaluation using PCNA for classifying cells into proliferating cells and nonproliferating cells in combination with AgNORs staining provided information of greater values to the malignancy assessment of gastric carcinoma as compared with the standard AgNORs single staining
