[Comparison of DNA index using flow cytometry between primary tumor and its metastatic regional lymph node in human...

Flow cytometric determination of DNA ploidy was performed on paraffin-embedded specimens of primary tumor (Group A) and its metastatic lymph nodes (Group B) in 30 surgically resected cases, and the DNA index (DI) was compared between these two groups. In 25 of 30 cases (83.3%), all DI observed in Group B were also found in Group A; and in the remaining 5 cases, a series of DI not found in Group A were observed in group B. They were all poorly differentiated adenocarcinomas, 4 of which exhibited serosal invasion and prominent lymphatic permeation in their wall. In 28 cases (93.3%), the modal DI value in the primary tumor was also found in their corresponding metastatic lymph node, the frequency of which revealed a statistically significant difference from 18 cases (60%) in terms of median DI value, and from 10 cases (33.3%) in terms of maximum DI value (p < 0.01). It was suggested that the modal DI value in the primary tumor could signify an important clone relating to lymph node metastasis. No significant DI difference was observed in comparison of a series of DI seen in n1(+) and n2(+) group of metastatic regional lymph nodes.