DEFINING THE EXTENT AND NATURE OF CYTOGENETIC EVENTS IN PROSTATIC ADENOCARCINOMA - PARAFFIN FISH VS METAPHASE ANALYSIS

A comparative study of primary prostatic tumors utilizing conventional metaphase analysis of prostate tumor cultures and fluorescence in sit u hybridization (FISH) analysis of paraffin-embedded tissue sections r evealed significant differences in type and extent of cytogenetic aber rations. Clonal trisomy 7 was identified in two tumors by metaphase an alysis of prostate cultures, but not confirmed in either case by FISH analysis. True gain of chromosome 8 was revealed by FISH analysis in m alignant epithelium of four tumors but not in adjacent normal or hyper plastic glands. Neither gain nor loss of this chromosome was observed by metaphase analysis in any of the tumors. Significant monosomy and n ullisomy of chromosome 10 was identified in one case by FISH, but no c ells with gain or loss of chromosome 10 were observed by metaphase ana lysis. Significant loss of the Y chromosome was revealed in one tumor by FISH, but no cells with -Y were identified by metaphase analysis. C lonal loss of the Y chromosome was identified in two other tumors by m etaphase analysis. Paraffin FISH analysis of these tumors revealed ove rall monosomy in both, although in one tumor there was extensive nodul ar loss of the Y chromosome. Paraffin FISH analysis permits identifica tion of cytogenetic aberrations in areas identified as carcinoma (CaP) , prostatic intraepithelial neoplasia (PIN), and benign prostatic hype rplasia (BPH). This technique appears more informative in defining the true extent and nature of cytogenetic aberrations in prostate cancer than metaphase analysis of prostate tumor cultures.