Diagnostic significance of fluorocytophotometric DNA ploidy analysis of gastric cancer with special reference to its comparison with clinical and histopathological diagnosis

Mithramycin binds stoichiometrically with G-C pairs of nucleotides, thus it is useful for nuclear DNA fluorocytophotometry. In the present study, relationships between clinical features and nuclear DNA ploidy values were explored in 80 gastric cancer cases. For the first time, nuclear DNA ploidy values of tumor tissues even in the same gastric cancer were found to be not always identical, when those were determined at two different sites in the same layer or at two different depths of cancer invasion. The highest DNA ploidy values greater than 9C of the original tumors were significantly more frequently observed in advanced cancer than in early cancer. The highest DNA ploidy values greater than 12 degrees C of the original tumors were significantly more frequently observed in gastric cancer cases with lymph node metastases than in those without lymph node metastases. The highest DNA ploidy values of metastatic tumors in lymph nodes were significantly greater than those of the original tumors. The cell lines with very high nuclear DNA ploidy values, however, usually do not establish new stem lines in metastatic lymph nodes. Borrmann 2 gastric cancer which was clinically diagnosed as the localized type often showed much greater nuclear DNA ploidy values and higher incidence of metastases than Borrmann 3. Therefore, it is not true that Borrmann 2 gastric cancer is less malignant than Borrmann 3. When cancer cells invaded onto the peritoneal surface, through the serosal layer, the highest nuclear DNA ploidy values are significantly reduced for unknown reasons. Therefore, it should be kept in mind that the reduction of highest nuclear DNA ploidy values in these invasive types of gastric cancer patients does not necessarily mean a good clinical sign. Nuclear DNA ploidy analysis is the effective means of cell biological diagnosis for gastric cancer.