Heterogeneity in gastric carcinoma with special reference to DNA content and mitotic activity: histopathologic differentiation

DNA ploidy was microspectrophotometrically investigated in 46 patients with gastric carcinoma. Measurements of DNA content and mitotic index (MI) were examined in the mucosal, submucosal, muscularis propria, and serosal layers of tumors, respectively. The frequency of cells with values exceeding hexaploid chromosome (6c) and mitotic counting analysis revealed a significantly higher value in the serosa than in the mucosa. This tendency was not evident in differentiated type adenocarcinoma but was noted in those with the undifferentiated type. There were 37 tumors (80.0%) with the same DNA distribution pattern in every layer of the stomach (homogeneous DNA ploidy). Heterogeneity of DNA ploidy was observed in nine tumors (20.0%). Carcinoma with heterogeneous DNA ploidy manifested a significantly higher incidence of metastasis to lymph nodes than did those with the homogeneous type. Characteristically, there was venous permeation preponderance in the differentiated type and peritoneal dissemination preponderance in the undifferentiated type. This evidence of DNA heterogeneity in gastric carcinoma tissue suggests a possible correlation with metastatic behavior.