A COMPARATIVE-STUDY OF CELL-PROLIFERATION MARKERS IN BREAST CARCINOMAS

Aims-To investigate the tumour cell proliferative index obtained by im munestaining of paraffin wax sections of 30 cases of breast carcinoma with monoclonal antibodies MIB1, KiS1 and KiS5, and polyclonal Ki67 an tisera to the Ki67 antigen and 19A2 and PC10 antibodies to proliferati ng cell nuclear antigen and the possible correlation between these ind ices and that of monoclonal Ki67 antibody in frozen sections of the sa me tumours. Methods-All tumour samples had been uniformly fixed and pr ocessed and sections were subjected to microwave antigen retrieval bef ore immunostaining in all instances except for monoclonal Ki67 antibod y which was used in cryostat sections. Tumour cell proliferative indic es were evaluated by two independent examiners, each counting 500 tumo ur cells with the aid of a cross-hatched grid. Results-Proliferative i ndices obtained with MIB1, polyclonal Ki67, KiS1, and KiS5 correlated with those obtained with monoclonal Ki67 in frozen sections. Prolifera tive indices obtained with monoclonal 19A2 and PC10 showed no correlat ion with those of monoclonal Ki67 antibody. The staining obtained with MIB1 was the most intense and the easiest to read. Conclusions-Monocl onal antibodies MIBI, KiS1 and KiS5 and polyclonal Ki67 antiserum appe ar to be suitable substitutes for monoclonal antibody Ki67 in the asse ssment of tumour cell proliferative index. As these reagents are all i mmunoreactive in paraffin wax sections, they overcome the requirement for frozen tissue for immunostaining with monoclonal Ki67.