By cytogenetic analysis, structural and numerical aberrations of chromosomes 1, 7, 8, 10, 16, and Y~ were identified in about 25% of the prostate carcinomas (PCs) studied. However, this figure is probably an underestimation of the true extent of the aberrations. This is because of selective isolation and preferential in vitro growth of nonmalignant prostate epitheliumY The use of interphase cytogenetic techniques for characterization of uncultured PC material has been stimulated by these findings. Application of in situ hybridization with centromere-specific DNA probes to fixed sections of PC has shown numerical aberrations for chromosomes 1,7,8,10,12,17,18, X, and y4~7 The finding of numerical aberrations in different chromosomes is not surprising because about 50% of the PCs have an aneuploid DNA content. 8 In the present study, the authors investigated numerical changes of chromosomes 1,7,8,10,18, and Y using fluorescence in situ hybridization (FISH) with centromere-specific DNA probes on nuclear suspensions of fresh tissue samples from 11 benign prostatic hyperplasia (BPH) and 43 PC patients. Selection of this chromosome panel was based on evidence from the literature and previous studies 9-a2 that these chromosomes were possibly implicated in PC development or progression. Study of recurring patterns of specific chromosomal aberrations might provide new information about the genetic events involved in these processes.The BPH specimens showed no deviation fromFrom the

The frequency of aneuploid cells in cultured prostate carcinoma specimens was investigated. Ploidy distribution of the original tissue was established by flow cytometry (FCM). Fluorescence in situ hybridization (FISH) of chromosome I was applied to directly isolated and cultured cells to investigate whether any modifications in the ploidy distribution of chromosome I took place during tissue culture. In six tumor specimens that were diploid by FCM and FISH, no differences were found in the ploidy distribution of chromosome I before and after tissue culture. In eight tumors that were aneuploid by FISH, the percentage of aneuploid nuclei was significantly reduced from 28.0 +/- 15.0 (range 13-59%) in uncultured cells to 9.1 +/- 4.4 (range 4-18%) after tissue culture. The reduction of aneuploid nuclei ranged from 44 to 85%, which means that the majority of the aneuploid cell populations that were observed in the original specimens were undetectable in cultured samples. This suggests a preferential growth of normal epithelial cells. The data presented can explain the high percentage of diploid karyotypes usually found in short-term cultured prostate carcinoma specimens.

Stromal cells from the prostate were recently shown to inhibit clonal growth of the prostatic carcinoma cell lines PC-3 (hormone-independent) and LNCaP (hormone-sensitive) in coculture. Our study revealed that stromal cell-conditioned medium strongly inhibited proliferation of PC-3 and LNCaP cells when grown in monolayer culture. Antiproliferative activity was found to be reversible, and was produced specifically by prostatic stromal cells and not by stromal cells derived from skin, foreskin, uterus, kidney, and Wilms' tumor. Inhibition was not species-specific, since the cell lines AT-2.1 and MATLyLu, derived from the Dunning rat prostate tumor, were also sensitive. No inhibition, however, occurred on breast and renal carcinoma cell lines, suggesting a prostate-specific action. The putative inhibiting factor(s) could be concentrated and partially purified by ammonium sulfate precipitation. The possible role in stromal control of epithelial cell proliferation is discussed.

Nuclear suspensions of 42 prostate carcinoma specimens obtained at surgery were used to investigate loss and gain chromosomes 1, 18, and Y by fluorescence in situ hybridization (FISH) with centromere-specific probes. The outcome of FISH analysis was correlated with clinical parameters and the relationship between DNA-FCM (ploidy at cellular level) and FISH (ploidy of individual chromosomes) was assessed. Significant loss of chromosomes 1 and 18 was infrequent (respectively, three and five cases), but 53% of the tested specimens showed loss of Y. Loss was not correlated with DNA ploidy. Significant gain occurred in 36% (chromosome 1), 63% (chromosome 18), and 28% (Y) of the specimens. Gain of chromosome 18 was shown in DNA diploid (7/14) and aneuploid tumors (18/26), while gain of chromosomes 1 and Y was nearly restricted to DNA aneuploid specimens. Significant unbalance between these chromosomes occurred in 11 cases. Most cases which had significant gain of chromosome 1 or 18 showed trisomic as well as tetrasomic cells. Simultaneous loss of some and gain of other investigated chromosomes is suggestive of clonal heterogeneity and/or multiclonality. This was observed in eight tumors. Correlation between DNA-FCM and FISH was best for the Y chromosome. DNA-FCM showed more aberrant histograms with increasing stage and grade of tumors. The presence of numerical aberrations of the investigated chromosomes however, seemed independent of clinical grade or stage.

Using chromosome banding and fluorescence in situ hybridization (FISH) with painting probes, sequential cytogenetic analysis was performed of two novel prostate cell lines, PZ-HPV-7 and CA-HPV-10, established by human papillomavirus (HPV) 18 DNA transformation. PZ-HPV-7 originates from a normal diploid prostate epithelial cell strain. PZ-HPV-7 progressed from an initial diploid to a hypertetraploid chromosome number with a relative gain of chromosomes 5 and 20 (7 to 8 copies each). Structural changes were limited; 3p- (2 copies), 3q- (1 copy), and possibly a der(16p;12q). CA-HPV-10 originates from an epithelial cell strain derived from a high-grade human prostate cancer specimen, which showed several karyotypic abnormalities including an extra Y chromosome and double minutes (dmin). In early passage the karyotype of CA-HPV-10 appeared unstable with a decreasing number of cells exhibiting dmin. In late passage the dmin were replaced by a large homogeneously staining region (hsr) on 9p+ marker. The hsr was shown by FISH to be of chromosome 1 origin. The modal number was mainly hypertriploid (72, range 69 to 75). Loss of Y was remarkable (0 to 1 copy). Consistent markers included two copies each of del(1)(q12q31) and der(9)t(1;9)(?;p22), and one der(11)t(4;11) (?;q21). HPV type 18 genomic integration sites were identified on 1p for PZ-HPV-7 and on the 9p+ marker for CA-HPV-10. In conclusion, both PZ-HPV-7 and CA-HPV-10 showed clonal cytogenetic changes. These two cell lines constitute a novel in vitro model to study the mechanisms involved in human prostate carcino-genesis.