Fluorescence in situ hybridization to assess transitional changes of aneuploidy for chromosomes 7, 8, 10, 12, 16, X and Y in metastatic prostate cancer following anti-androgen therapy

There have been few detailed studies conducted on the cell population in relation to cytogenetic changes between the pre- and post-treatment periods in patients with prostate cancer. We investigated numerical chromosome changes associated with anti-androgen therapy, using fluorescence in situ hybridization (FISH). FISH using chromosome-specific centromeric probes was used to assess transitional changes in the frequency of aneuploidy for chromosomes 7, 8, 10, 12, 16, X, and Y in prostate cancer during the pre- and post-treatment periods. Gains of chromosomes 7, 8 and 12 were notable in the pre-treatment samples (8 out of 9 cases in chromosome 7; 8 out of 9 cases in chromosome 8; 7 out of 9 cases in chromosome 12), while a notable reduction in the number of cells with extra copies of these chromosomes was observed in post-treatment specimens. Other chromosomes did not show noticeable chance in their FISH signals at each phase of clinical treatment in all 9 cases. Changes in cell number with high ploidies of chromosome 7, 8 and 12 reflect the clinical effects of antiandrogen therapy at the early phase, which might explain the androgen dependency of metastatic prostate cancer cells.