Numerical chromosomal changes in metastatic prostate cancer following anti-androgen therapy: Fluorescence in situ hybridization analysis of 5 Japanese cases

We used fluorescence in situ hybridization with centromere-specific probes for chromosomes 7, 8, 10, and Y to determine the copy number of these chrom osomes in metastatic prostate cancers of five Japanese cases. Freshly prepa red samples were obtained from prostate needle biopsies at different phases of clinical treatment; pretreatment, 1 week, 4 weeks, 12 weeks, 24 weeks p ost-treatment (PT), and clinical relapse. Gain of chromosomes 7 and 8, as n oted in pretreatment samples; however, in post-treatment specimens (four of five cases), a remarkable reduction in the number of cells with extra copi es of these chromosomes was detected. This decrease in the number of cells with additional chromosome 7 and 8 signals was correlated with the clinicoh istopathological findings until 4 weeks PT. Chromosomes Y and 10 did not sh ow numerical aberrations before treatment or changes in cells with aneusomy after treatment in all five cases. Our results suggest that gains of chrom osomes 7 and 8 correlate with high grade and stage, and that changes in the cell number with aneusomy of chromosomes 7 and 8 reflect the clinical effe cts of anti-androgen therapy at an early phase, which may also indicate the androgen dependency of prostate cancer cells. (C) 2000 Elsevier Science In c. All rights reserved.