Interphase cytogenetics of prostate cancer: fluorescence in situ hybridisation (FISH) analysis of Japanese cases

The endothelial nitric oxide synthase Glu-298-Asp polymorphism and its mRNA expression in the peripheral blood of patients with prostate cancer and benign prostatic hyperplasia

BACKGROUND

The endothelial nitric oxide synthase (ecNOS) has an important role in vascular development and in the carcinogenesis process of prostate cancer (PCa). The nitric oxide (NO) production may promote cancer progression by providing a selective growth advantage to tumor cells, by angiogenic stimulus and by direct DNA damage.

METHODS

The present study aimed at evaluating the ecNOS Glu-298-Asp polymorphism by the PCR-RFLP technique, associating genotypes with gene expression levels and the tumor biomarker, Prostate Cancer Antigen (DD3), through semi-quantitative RT-PCR. Pre-surgical peripheral blood samples from 160 patients were analyzed: 84 PCa, 11 prostate intraepithelial neoplasia (PIN) and 65 benign prostatic hyperplasia (BPH).

RESULTS

The GG and GT Glu-298-Asp genotypes were associated with positive DD3 expression in the peripheral blood, presenting a 3.32-fold higher risk of PCa occurrence. There was no association between genotypes and ecNOS mRNA expression levels; however, the presence of the G allele is closely related to the hematogenous dissemination event of tumoral cells, as evidenced by the DD3 positivity. The higher G allele frequency among pT3 and pT4 staged PCa patients suggests that this would be associated with advanced phenotypes of the disease and may also be contributing to higher NO levels, causing cancer progression.

CONCLUSIONS

The G allele may have a secondary influence on the prostate cancer predisposition, but an essential role on the event of tumor cells hematogenous dissemination, probably due to the angiogenic stimulus.

Molecular pathology of prostate cancer

The molecular pathology of prostate cancer is complex; not only are multiple genes involved in its pathogenesis, but additional environmental factors such as diet and inflammation are also involved. The exhaustive research into prostate cancer to date has demonstrated a complex interaction of multiple genes and environmental factors, some of which may be more important in individual prostate cancer cases. This is an exciting era, with the emergence of new investigative tools such as DNA microarray technology and the application of the field of proteomics to the study of human cancers. Knowledge of genetic changes underlying the initiation, development, and progression of prostate cancer is accumulating rapidly. With increasing knowledge, it may be possible to distinguish indolent from aggressive prostate tumours by molecular fingerprinting. This review discusses the most consistently reported molecular pathological findings in hereditary and sporadic prostate cancer, together with new concepts and technologies.

Overexpressing leptin genetic polymorphism (-2548 G/A) is associated with susceptibility to prostate cancer and risk of advanced disease

BACKGROUND

Leptin has been consistently associated with angiogenesis and tumoral growth. A G/A single nucleotide polymorphism (SNP) at the -2548 site in leptin gene (LEP) is associated with overexpression of leptin (A-allele).

METHODS

We evaluated DNA samples from 268 (536 alleles) unrelated individuals, 118 healthy controls (HCs) and 150 prostate cancer (PC) patients, for leptin gene (LEP) locus -2548 genotypes.

RESULTS

We found an overrepresentation of the A-allele in PC patients and that there is a significantly higher risk for PC among A carriers (OR = 1.60; confidence interval (CI), 1.13-2.28, P = 0.008). Linear trend analysis showed that quantitative increase of A-allele presence was associated with significantly higher risk for PC (P = 0.003) in heterozygous (OR = 2.11; CI, 1.20-3.71) and homozygous (OR = 2.93; CI, 1.27-6.75) genotypes. Furthermore, the AA and AG genotypes represent significantly higher risk (OR = 4.67; CI, 1.69-12.88 and OR = 2.58; CI, 1.19-5.58, respectively) for advanced disease.

CONCLUSIONS

According to our results we hypothesize that the polymorphism in LEP gene may be relevant to PC risk and progression, supporting the hypothesis for leptin involvement in cancer ethiopathogenesis.

Detection of Chromosomal Aberrations in Prostate Cancer by Fluorescence In Situ Hybridization (FISH)

PURPOSE

Fluorescence in situ hybridization (FISH) is a powerful tool for quantitative analysis of chromosomes and genes and can be applied in a variety of specimens, including cell cultures, isolated nuclei from fresh and fixed tissues, and histological tissue sections. For detection of numerical chromosome aberrations, we examined prostatic cancer samples at our department. In addition, we also observed primary and secondary aberrations taking part in the initiation and progression of tumours.

MATERIALS AND METHODS

FISH using chromosome-specific alpha-satellite DNA probes for chromosomes 7, 8, 9, 10, 17, X and Y was performed on 19 prostatic cancer and 19 benign prostatic hyperplasia (BPH) samples obtained from transurethral resection (TUR) and archival paraffin-embedded blocks.

RESULTS

Numerical aberrations were observed in 41% of the tumours studied. A range of aberrant copy numbers of chromosome 9 (68%), 7 (63%), 8 (58%), 17 (37%), Y (32%) and 10 (26%) was observed. We did not observe significant aberrations in BPH samples. In prostate cancer patients, chromosomes 7 (47%), 8 (58%) and 9 (63%) were monosomic by FISH. Monosomy 8 and 9 were significant differences (p>0.05) between prostate cancer and BPH patients.

CONCLUSIONS

FISH analysis could be observed an one of strongest methods of analysis in detecting numerical aberrations of individual chromosomes with application to paraffin-block samples, metaphase and, interphase nuclei. To our knowledge, this analysis is firstly studied in Turkish patients. Therefore, results of this analysis may be important for Turkish patients.

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 chromosomes in metastatic prostate cancers of five Japanese cases. Freshly prepared samples were obtained from prostate needle biopsies at different phases of clinical treatment; pretreatment, 1 week, 4 weeks, 12 weeks, 24 weeks post-treatment (PT), and clinical relapse. Gain of chromosomes 7 and 8, as noted in pretreatment samples; however, in post-treatment specimens (four of five cases), a remarkable reduction in the number of cells with extra copies of these chromosomes was detected. This decrease in the number of cells with additional chromosome 7 and 8 signals was correlated with the clinicohistopathological findings until 4 weeks PT. Chromosomes Y and 10 did not show numerical aberrations before treatment or changes in cells with aneusomy after treatment in all five cases. Our results suggest that gains of chromosomes 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 effects of anti-androgen therapy at an early phase, which may also indicate the androgen dependency of prostate cancer cells.

Fluorescence in situ hybridization evaluation of c-myc and androgen receptor gene amplification and chromosomal anomalies in prostate cancer in Japanese patients

BACKGROUND

Oncogene amplification and chromosomal anomalies are found in many solid tumors and are often associated with aggressiveness of cancer. We evaluated the frequency and the association of c-myc and androgen receptor (AR) gene amplification and gain of chromosome 8 or X in prostate cancer in Japanese patients.

METHODS

We examined a total of 42 prostate cancer specimens, using fluorescence in situ hybridization (FISH). Dual-labeling hybridization with a directly labeled centromere probe for chromosome 8 or X together with a probe for the c-myc or AR locus was performed.

RESULTS

Gain of chromosome 8 was identified in 54.8% of specimens and was associated with Gleason sum and nuclear anaplasia in untreated prostate cancers. c-myc gene amplification was found in 14.3% of specimens. Gain of chromosome X was identified in 42.9% of specimens. AR gene amplification was detected in 0 of 37 untreated prostate cancers, but in 1 of 5 hormone-refractory prostate cancers.

CONCLUSIONS

Our results suggest that c-myc and AR gene amplification and gain of chromosome 8 or X may be associated with the development and progression of prostate cancers. These results obtained in Japanese cases are consistent with the results observed in prostate cancer in Western countries.