DNA IMAGE CYTOMETRY AND THE EXPRESSION OF PROLIFERATIVE MARKERS (PROLIFERATING CELL NUCLEAR ANTIGEN AND KI67) IN NON-HODGKINS-LYMPHOMAS

We have analyzed DNA content and proliferative activity in morphologic ally defined cell subpopulations of 74 non-Hodgkin's lymphomas (NHL) a nd 29 reactive lymph nodes using DNA image cytometry and antibodies to proliferative markers (proliferating cell nuclear antigen (PCNA) and Ki67). Thirteen (18.6%) of 70 NHL cases were aneuploid. The follicular center cell-derived lymphomas with DNA aneuploidy had DNA indices (DI ) predominantly in the tetraploid region, whereas aneuploid high-grade (HG) NHL presented DNA histograms with multiple aneuploid stemlines. In aneuploid centrocytic-centroblastic (CB/CC) NHLs, DNA aneuploidy wa s found exclusively in centroblasts, whereas centrocytes in these case s were diploid. Percentages of cells in S and G(2)/M phase in chronic lymphocytic leukemia (CLL), immunocytoma (IC), centrocytic NHL (CC), a nd centrocytes from CB/CC were low (<5%), whereas the respective value s for centroblasts in CB/CC and in malignant cells of HG NHL were simi lar to those of large lymphoid cells in the reactive lymph nodes (mean , 39.5%, 36.6%, and 53.5%, respectively). The mean percentage of PCNA positive cells in CLL, IC, and CC was 4.9%. In the follicles of CB/CC NHLs there was, on average, 56.9% of PCNA positive centroblasts and 8. 1% of PCNA positive centrocytes. In HG NHL, the mean percentage of PCN A positive lymphoma cells was 27.9%. A positive correlation was found between percentages of cells in S and G(2)/M phase and cells positive for PCNA (P < 0.001). There was also a significant correlation between percentages of Ki67 (mean, 19.2%) and PCNA positive cells (mean, 17.7 %) (P < 0.01). The histogram of frequency distribution for the S and G (2)/M fractions and for fractions positive for PCNA was asymmetric, wi th the cut-off value at approximately 30%. We conclude that DNA image cytometry detects aneuploidy even in small subpopulations of lymphoma cells and that anti-PCNA antibody can be used to determine proliferati ve fraction in paraffin-embedded material from NHL.