MIB-1 AND S-PHASE CELL FRACTION PREDICT SURVIVAL IN NON-HODGKINS-LYMPHOMAS

The monoclonal antibody anti-Ki67 is used to detect proliferating cell s, but its main limitation is the requirement of fresh-frozen material . On a series of patients with non-Hodgkin's lymphoma, we used a Ki67 equivalent monoclonal antibody, the recently proposed MIB-1, on formal in-fixed histopathological material using microwave antigen retrieval. MIB-1 expression was analysed in relation to other proliferation indi ces, such as autoradiographic H-3-thymidine labelling index ((3)HTL1) and flow cytometric S-phase cell fraction (FCM-S) and to pathological status. Moreover, the prognostic relevance of the cell kinetic indices was defined in uni-and multivariate analyses including histology and tumour stage. The relationship between MIB-1 index and the other proli feration indices was statistically significant even though the correla tion coefficient was around 0.6. The MIB-1 index was also related to t he REAL (Revised European American Lymphoma) classification, but not t o the Ann Arbor stage classification. Univariate analysis showed that the MIB-1 index was a significant predictor of 6-year survival in the overall series and in distinctly analysed low-grade and high-grade lym phoma subgroups. With regard to S-phase indices, (HTLI)-H-3 was a powe rful prognosticator in patients with high-grade histologies and FCM-S in patients with low-grade histologies. Multivariate analyses revealed that MIB-1 indiex, (HTLI)-H-3 and FCM-S retained their prognostic sig nificance independent of histology. In conclusion, the MIB-1 antibody provides prognostic information in non-Hodgkin's lymphomas and has the main advantage that it can be used in formalin-fixed, paraffin-embedd ed specimens.