Prognostic significance of DNA flow cytometry in non-Hodgkin's lymphoma

A series of cases of non-Hodgkin's lymphoma (NHL) were studied by morphology and flow cytometry. The DNA analysis was performed by applying a trypsin digestion method to archival paraffin-embedded samples. DNA aneuploid tumors constituted 47.4% of the total cases, and the frequency in the intermediate and the high malignant grade groups (51.9%, 76.8%) were significantly higher than that of the low grade group (17.6%; P less than 0.05). The S phase fraction (SPF) increased significantly with a high histological malignant grade (P less than 0.005). The mean SPF values of the low, intermediate and high grade lymphomas were 6.5 (0.6-18.8)%, 13.5 (3.2-37.3)% and 23.4 (4.4-41.4)%, respectively. Differences in ploidy status were not associated with survival rate. The survival rate of the cases with high SPF value in all cases of our series and low grade group of NHLs tended to become lower (P = 0.1 and 0.08, respectively). These results suggest that the flow cytometric analysis of DNA content should be a useful means for prediction of prognosis in non-Hodgkin's lymphoma.