Aneusomy of chromosomes 7 and 17 detected by fish in prostate cancer and the effects of selection in vitro

Abstract

Twenty prostate tumor specimens, obtained from radical prostatectomies, and two lymph node metastases were examined by classical and molecular cytogenetic methods. A sample from each tumor was analyzed histologically and used for touch preparations. Adjacent samples were used for preparation of single-cell suspensions before cell culture (DirFISH) and for establishing cell cultures, which were subsequently harvested for classical G-banding analysis. Fluorescence in situ hybridization (FISH) was performed on touch preparations, DirFISH, and cells obtained from tissue culture. Biotinylated pericentromeric probes for chromosomes 7 and 17, in addition to a digoxigenin-labeled X-chromosome probe, were used in a dual-color FISH assay. The results indicated that, in uncultured tumor cells, chromosome 17 was lost in 55% of specimens, chromosome 7 was gained in 16% of specimens, and 9% of specimens showed large tetraploid populations. After cell culture, 23% of specimens showed loss of chromosome 17, no specimens showed gain of chromosome 7, and no tetraploid populations were present. This study suggests that loss of chromosome 17 may play an important role in the development of prostate cancer, and that genetic changes observed after selection in vitro may not represent those in the original tumor.

Androgen Receptor Expression, Proliferation Index and Aneuploidy in Tissue Explant Cultures Derived Prostate Carcinoma Cells Co-Cultivated on Membranes

“…We had found a preferential growth of diploid cells with loss of the aneuploid cell populations either immediately after cell culture initiation or early during progressive subcultivation. Similar observations were reported by other groups [5,6,13,14].…”

“…Only actively growing cells can be analyzed by standard cytogenetic studies. The majority of cell cultures derived from prostatic carcinomas have a low proliferation and exhibit a normal karyotype with chromosomal changes in less than 25% of all cases [13,27]. In contrast, DNA aneuploidy seems to be a more frequent event in prostatic adenocarcinomas when interphase cytogenetic analysis (FISH) was performed [10].…”

“…Only trisomy of chromosome 7 seems to be associated with poor prognosis and therefore may be an early event in tumorigenesis [28]. Jones et al [13] observed a loss of chromosome 17 in 53% of prostatic carcinomas in histological sections. During cell cultivation this value decreased maximally to an average of 23% [29].…”

Chromosomal Instability in Peripheral Blood Lymphocytes and Risk of Prostate Cancer

“…Initial studies suggested that f75% of prostate cancer tumors had normal male karyotypes; however, there is now evidence by subsequent analysis over cell culture times that normal cells seem to be selected for in vitro (4,5); therefore, growth of tumor cells was not ideal. Several candidate chromosomes have been suggested as playing a role in the development of prostate cancer, among which are chromosomes 1,7,8,10,17, and X (6-10).…”

RET rearrangements in papillary thyroid carcinomas and adenomas detected by interphase FISH

“…Fluorescence in situ hybridization (FISH) has been applied to the study of various solid tumors (Hopman et al, 1991;Jones et al, 1994;Wada et al, 1997), mainly for the detection of numerical chromosome aberrations by using centromeric probes. There have been very few reports of FISH studies on PTCs, namely, a characterization of a chromosome structural anomaly in the cell line TPC1 (Jossart et al, 1995(Jossart et al, , 1996 and a similar study in a PTC case (Lehmann et al, 1997).…”