MIB-1, KI67, AND PCNA SCORES AND DNA FLOW-CYTOMETRY IN INTERMEDIATE GRADE MALIGNANT-LYMPHOMAS

Aims-To verify the correlation between MIB-1, Ki67, and proliferating cell nuclear antigen (PCNA-PC10) scores and S-phase fraction in interm ediate grade non-Hodgkins lymphomas (Working Formulation F); and their reliability in differently processed tissues. Methods-Forty one non-H odgkin's lymphomas were classified as (F) intermediate grade malignant lymphomas according to the Working Formulation; mitotic counts and pe rcentage of large cells were assessed for each case. Sections from for malin fixed, paraffin wax embedded tissues were stained with anti MIB- 1 monoclonal antibody, after microwave oven processing, and anti-PCNA (PC10) monoclonal antibody using an avidin-biotin immunoperoxidase (AB C) method. One thousand cells from 10 representative fields were score d. Frozen sections from surgical specimens were stained with Ki67 mono clonal antibody using the ABC method; the fraction of Ki67 positive ce lls was calculated scoring 1000 cells. Flow cytometry analysis (FCM) w as performed on cell suspensions from fresh tissues. Correlations betw een data were estimated using linear regression. Results-A linear corr elation was found between MIB-1 and Ki67 scores (r = 0.92; p < 0.00001 ); between MIB-1 and PCNA scores (r = 0.79; p < 0.00001); and between MIB-1 score and S-phase fraction (r = 0.51; p = 0.0006). A linear corr elation was also found between Ki67 and PCNA scores (r = 0.85; p < 0.0 0001); between Ki67 score and S-phase fraction (r = 0.6; p = 0.0002). and between PCNA score and S-phase fraction (r = 0.74; p < 0.00001). A correlation was found between mitotic counts and MIB-1 (r = 0.56; p = 0.0001), PCNA (r = 0.51; p = 0.0007), or ki67 scores (r = 0.47; p = 0 .002); between the percentage of large cells and MIB-1 (r = 0.49; p = 0.0009), PCNA (r = 0.6; p = 0.00003), and ki67 scores (r = 0.53; p = 0 .0003) and S-phase fraction (r = 0.55; p = 0.0002). Conclusion-MIB-1, Ki67, and PCNA (PC10) scores and S-phase fraction are highly correlate d and equally well represent the proliferative activity of intermediat e grade non-Hodgkins lymphomas in differently processed material. MIB- 1 and PCNA strains can be applied even on small biopsy specimens. MIB- 1 produces homogenous staining without background; it also strongly st ains mitotic figures. It can be performed on routinely processed tissu es, permitting the simultaneous evaluation of the morphology and tumou r cell kinetics. The wide standard deviations of the proliferative ind ices found for intermediate grade NHL suggest that this category proba bly includes various degrees of malignancy.