Tumour cell proliferation rate as determined by MIB-1 antibody in Wilms' tumour.

Determination of neoplastic cell proliferation becomes an important and objective element of assessing malignancy of neoplasms and their response to therapy. The basic problem in the management of Wilms' tumours in children is selection of patients to appropriate risk groups. The purpose of the present study was to evaluate proliferation index in 35 Wilms' tumours determined immunohistochemically by using monoclonal antibody MIB-1. The final analysis included 39 preparations of formalin fixed and paraffin embedded tissue sections. Proliferation index of neoplastic cells was determined in blastema, epithelium and stroma of the tumours. We found a marked difference between low proliferation index in stromal cells and high proliferation index in blastemal and epithelial cells. In tumours after chemotherapy we found higher proliferation index in epithelial cells and lower index in blastemal cells as compared to tumours before chemotherapy. Higher proliferation index in blastemal cells and epithelial cells was associated with worse prognosis. Worse prognosis was seen in cases in which after chemotherapy proliferation index in blastemal cells was still high.