MULTIPARAMETER FLOW CYTOMETRIC ANALYSIS WITH DETECTION OF THE KI67-AGIN PARAFFIN-EMBEDDED MAMMARY CARCINOMAS

In the present study we describe a novel multiparameter flow cytometri c (FCM) assay to estimate the fraction of cycling cells in epithelial tumors derived from fresh frozen as well as archival material, To this end, MCF-7 cells as well as a series of breast carcinomas (n = 10; fr esh frozen as well as formalin fixed and paraffin embedded) were stain ed using a panel of different antibodies directed against the Ki67-Ag (DAKO/PC, MIB-1, Ki-S5, and poly-Ki67) for a 3-parameter cytokeratin/K i67-Ag/DNA FCM analysis. Whereas all Ki67-Ag antibodies work equally w ell in the methanol fixed cell line, MIB-1 and Ki-S5 epitopes are reta ined in cell suspensions mechanically derived from fresh frozen tissue , Only antibody Ki-SS shows specific nucleolar staining patterns in ce ll suspensions prepared by trypsin digestion of formalin fared, paraff in embedded tissue sections, A good correlation was found between the fractions of Ki67-Ag-positive epithelial cells measured in cell. suspe nsions derived from fresh frozen and the corresponding formalin fixed and paraffin embedded tumor samples, Furthermore, the fraction of Ki67 -Ag-positive epithelial cells as determined by S-parameter FCM correla ted very well with the Ki67-Ag-labeling index in paraffin embedded tis sue sections. (C) 1997 Wiley-Liss, Inc.