Background: This study was to evaluate bivariate bromodeoxyuridine (BrdUrd)/DNA flow cytometric analysis in detection of gastric carcinoma and to study the relations of cellular BrdUrd labeling indices (LI), G2/M-phase fraction (G2/MPF) and DNA ploidy pattern to lymphatic involvement, venous invasion and prognosis.
Methods: Fresh tumor samples from 60 patients with gastric carcinoma were analyzed by bivariate BrdUrd/DNA flow cytometry. The results were correlated with lymphatic vessel invasion, lymphatic node metastasis, the number of metastatic lymphatic nodes, and venous invasion. Propidium iodide (PI) was used as a fluorescent probe for total cellular DNA, and a monoclonal antibody against BrdUrd was used as a probe for BrdUrd incorporated into DNA. Fluorescent-labeled goat anti-mouse antibody was used as a second antibody. S-phase fractions were measured by in vitro BrdUrd labeling, and DNA ploidy and G2/MPF were also measured. Comparison of survival was performed with the log-rank test, the Chi-square test for qualitative data, and Student's t test for quantu data.
Results: BrdUrd LI and G2/MPF values were significantly higher in tumors with lymphatic vessel invasion than in those without invasion respectively (P < 0.01); the patients who had tumors with lymphatic vessel invasion showed a significantly poor prognosis (P < 0.01). Both BrdUrd LI and G2/MPF values were significantly higher in tumors with lymphatic node metastasis than in those without metastasis (P < 0.01). A statistical significant difference was noted in the 5-year survival rates between the patients with lymph node metastasis and those without metastasis. Compared with diploid carcinoma, the incidence of lymph node metastasis was significantly higher in aneuploid carcinoma (P < 0.05), and the patients with aneuploid carcinoma showed a significantly poor prognosis (P < 0.05). BrdUrd LI was significantly higher in patients with more than 5 metastatic lymph nodes than those with 1 - 4 metastatic lymph nodes (P < 0.05) and those without metastasis (P < 0.01). G2/MPF values in those patients either with more than 5 metastatic lymph nodes or 1 - 4 metastatic lymph nodes were higher than those without metastasis (P < 0.01 and P < 0.05). A statistical significance was seen in the 5-year survival rates among the patients with no metastatic lymph node, 1 - 4 metastatic nodes and more than 5 metastatic nodes (P < 0.01). G2/MPF values were significantly higher in patients with venous invasion than in those without invasion (P < 0.01).
Conclusions: Positive correlations exist between cellular BrdUrd LI, G2/MPF with lymphatic involvement and prognosis, and DNA aneuploid with lymphatic involvement and prognosis. The same was true between G2/MPF value and venous invasion in gastric carcinoma.