DIRECT COMPARISON OF BROMODEOXYURIDINE AND KI-67 LABELING INDEXES IN HUMAN TUMORS

Direct comparison of bromodeoxyuridine (BrdUrd) and Ki-67 labelling in dices was achieved by selecting similar areas from serial sections of human tumours. Fifteen patients were selected who had been administere d BrdUrd in vivo and both proliferation markers were assessed by immun ohistochemistry. The data show a good correlation between both BrdUrd LI and MIB-1 LI and T-pot (calculated using the flow cytometry derived duration of S phase) and MIB-1 LI. The contribution of BrdUrd LI to g rowth fraction varied as a function of proliferation characteristics, In tumours with a high LI, the number of DNA synthesizing cells repres ented half the growth fraction, whilst in tumours with lower LI's (<10 %) the ratio of DNA precursor labelled cells as a function of growth f raction fell to between 10% and 20%, T-pot showed a linear correlation with MIB-1/BrdUrd ratio with a slope approaching unity. It was appare nt that both intra- and interpatient variation in proliferation index was greater for BrdUrd labelling than for MIB-1 expression.