Relevance of the prostate-specific antigen (PSA) nanotest compared to the classical PSA test in the organized mass screening of prostate cancer.

OBJECTIVE: To assess the reliability of a new measurement of prostate-specific antigen (PSA) using a blotting-paper assay (nanotest) compared to the standard PSA immunoassay. SUBJECTS AND METHODS: The PSA level was measured in 205 men volunteers (median age 70 years, range 41-75) using a nanotest and a standard PSA immunoassay, collected at the same time; 30 microL of capillary blood placed on to a blotting paper were collected for the nanotest and sent by mail to the same laboratory for the two assays. The results were compared statistically using the Spearman test, the intraclass correlation coefficient and the Bland-Altman test. RESULTS: The nanotest threshold for an abnormal PSA level was 78 pg/mL, which corresponded to a standard PSA value of 3 ng/mL, with a sensitivity of 100%. There was a significant correlation (r = 0.98, Spearman test; P < 0.001) between the nanotest and the standard PSA assay. The intraclass correlation coefficient was 0.87. The Bland-Altman test showed a good agreement between the nanotest and the standard PSA assay, but there was an increasing proportional difference with increasing PSA value. CONCLUSION: There was a very high correlation between the nanotest and the standard PSA assay, especially for standard PSA levels of <5 ng/mL. Economic and clinical studies are indicated to confirm the utility of the nanotest in organized mass screening of prostate cancer.

High frequency of allelic losses in high-grade prostate cancer is associated with biochemical progression after radical prostatectomy.

Loss of heterozygosity (LOH) is the most consistent genetic change in prostate cancer (CaP). We aimed, to correlate specific LOH and the overall LOH frequency, to disease progression after radical prostatectomy (RP) in high-grade CaP. Between January 1990 through December 1998, 126 patients who underwent RP (cT1-T2), Gleason 8-10, were pT3, or pN1, or SM(+) (surgical margins). Nine were lost of follow-up, 39/117 (33%) had no biochemical progression (mean follow-up: 45 months). After exclusion for preoperative PSA >50 ng/mL, a case-control study was designed by matching 26 of these cases with 26 similar patients without biochemical progression (criteria: pT, pN, year of surgery). Using microsatellite markers, LOH were assessed on six chromosomal regions (7q31, 8p22, 12p13, 13q14, 16q23.2, 18q21). No prognostic value was associated with LOH at any one specific locus. However, the overall LOH frequency (five classes, cutoff of 60%), was significantly higher if progression (P = 0.02; P = 0.03) in SM(+) patients, and was near statistical significance (P = 0.08; P = 0.07) for the overall case-control population. In multivariate analysis (overall population), the overall LOH rate > or =60% was independently associated with progression [P = 0.035; Odds Ratio (OR) = 5.54]. An overall LOH rate > or =60% predicted poor outcome in 85% of SM(+) patients and 69% of the whole population. Our results suggest that the overall rate of LOH at chromosomal "hot spots" is more likely to be predictive of recurrence than the presence of LOH at any one particular locus. Moreover, the identification of a threshold of LOH could help in predicting patients with poor outcome who may be candidates for local or systemic adjuvant therapies.

Extensive analysis of the 7q31 region in human prostate tumors supports TES as the best candidate tumor suppressor gene.

Loss of heterozygosity (LOH) on chromosome arm 7q31 is found in many prostate tumors. Such alterations are generally associated with inactivation of tumor suppressor genes. It has been shown previously that the main region of LOH at 7q31 spans the interval between the D7S486 and D7S2460 microsatellite loci, which contains several candidate tumor suppressor genes (TSG) such as TES, CAV2, CAV1, MET, CAPZA2, ST7 and WNT2. We tested 41 human sporadic prostate tumors for 7q31 LOH by using 5 polymorphic markers overlapping the critical region and used a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay to study the expression of the 7 candidate TSGs located in this genomic region. We found that CAV1, CAV2, MET and TES mRNA expression was lower in prostate tumors than in normal prostate tissues. Our immunohistochemical results and previously published data on the compartmental expression of these messenger RNAs in stromal and epithelial cells suggest that TES is the best candidate tumor suppressor gene at 7q31.

Gene expression profiling in clinically localized prostate cancer: a four-gene expression model predicts clinical behavior.

PURPOSE: New diagnostic and prognostic molecular markers are required for prostate cancer, one of the most common male malignancies in Western countries. Gene expression profiling may help to identify genes involved in prostate carcinogenesis, yield clinical biomarkers, and improve tumor classification. EXPERIMENTAL DESIGN: To identify fundamental differences between normal and neoplastic prostate tissue, we used real-time quantitative RT-PCR assays to quantify the mRNA expression of 291 selected genes in samples of normal prostate and of well-documented primary, clinically localized prostate tumors. RESULTS: Forty-six genes showed significantly different expression in tumors relative to normal prostate. The dysregulated genes belong notably to the extracellular membrane and extracellular membrane remodeling categories and are involved in angiogenesis. Furthermore, we obtained a four-gene (XLKD1/LYVE1, CGA, F2R/PAR1, and BCL-G) model that discriminated between the seven patients with and the seven patients without relapse, independently of stage and grade. CONCLUSIONS: Some dysregulated genes are good candidates for use as molecular markers and/or therapeutic targets. Furthermore, differential gene expression profiling of clinically localized prostate tumors from relapsing and nonrelapsing patients identified a set of four genes with a pattern of expression that defines a molecular signature that could predict the clinical behavior of this disease.

Association study of polymorphisms in the human estrogen receptor alpha gene and prostate cancer risk.

OBJECTIVES: Prostate cancer is a very common hormone-related malignancy in Western countries. It is initially dependent on androgen stimulation but in vitro growth of prostate cancer cells are also dependent on estrogen. Our goal was to elucidate if some polymorphisms of estrogen receptor alpha gene might be associated with the risk of prostate cancer. METHODS: Using DHPLC techniques, each coding exon of the estrogen receptor alpha gene was screened for new polymorphisms in germline DNA from 96 healthy controls and 96 sporadic prostate cancer cases. Identified polymorphisms were then genotyped and their distribution compared between the two populations. RESULTS: Thirteen polymorphisms were identified. A difference was found in the distribution of one newly identified polymorphism, namely a GGGA repeat located in the first intron of the gene. The common wild type genotype consisted of two alleles with five GGGA repetitions (5/5 genotype). Indeed this 5/5 genotype was found in 294/296 controls (99.3%) and 285/294 patients (96.9%; OR, 4.6; 95% CI, 0.99-21.67). Among the nine patients with a different genotype, one was 4/5, seven were 5/6 and one was 6/6. CONCLUSION: These results suggest that variants of the GGGA polymorphism from the estrogen receptor alpha gene may be associated with an increased risk of developing prostate cancer.

Extensive analysis of the 13q14 region in human prostate tumors: DNA analysis and quantitative expression of genes lying in the interval of deletion.

BACKGROUND: Loss of heterozygosity (LOH) on chromosome arm 13q14 is one of the most consistent genetic alterations in sporadic prostate cancer. This alteration may be involved in prostate oncogenesis through inactivation of one or more tumor suppressor genes (TSGs). Candidate gene expression is an approach to focus the search for TSGs in this region. METHODS: We tested 41 human sporadic prostate tumors for 13q14 LOH by using seven polymorphic markers overlapping the critical region and used a real-time quantitative RT-PCR assay to study the same tumors for expression of the 31 genes located in this genomic region (localized by the Human Genome Project Working Draft). RESULTS: Allelic loss on at least one locus was found in 18 (41%) of the 41 tumor DNAs. Only four genes (ITM2B, CHC1L, KIAA0970, and LOC51131), located in the region most frequently deleted in prostate carcinoma, showed a significant difference in expression between normal and neoplastic prostate tissues. CONCLUSIONS: Given their location in the LOH hotspot, as indicated by our genomic analysis, ITM2B, CHC1L, KIAA0970, and LOC51131 are candidate tumor suppressor genes in this region. ITM2B that showed a significant association (P < 0.005) between expression and LOH at the corresponding locus could, furthermore, be the main target of the observed LOH at 13q in prostate tumors.

Quantification of expression of netrins, slits and their receptors in human prostate tumors.

Recently, DCC (Deleted in Colorectal Cancer) protein has been forwarded as a receptor for netrin. The Netrin/DCC complex is critical for axon guidance and cell migration. In the developing nervous system, netrin protein secreted by midline cells attracts commissural axons by activating the DCC receptor on growth cones. This attraction can be switched to repulsion or silenced completely, depending on the DCC binding partner. The potential suppressor function of DCC in prostate tumorigenesis, through a still unknown mechanism, prompted us to quantify the expression of several genes involved in this axon guidance pathway. The relative expression levels of DCC, NEO1, NTN1, NTN2L, NTN4, UNC5C, Slit1, Slit2, Slit3, Robo1 and Robo2 were simultaneous quantified in 48 tumors and 7 normal prostate tissues by using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). A reduction in DCC, NEO1, NTN1 and NTN4 expression was observed in prostate tumors, while many of the same prostate tumors over-expressed either Slit genes or their receptors, Robo.

Impact of constitutional genetic variation in androgen/oestrogen-regulating genes on age-related changes in human prostate.

OBJECTIVE: Benign prostatic hyperplasia (BPH) is the most common benign tumour in ageing men. While the etiopathology remains unsolved, a disruption in the endocrine/autocrine-paracrine prostatic homeostasis, involving steroid hormones, contributes to the pathogenesis of BPH. DNA polymorphisms in genes involved in hormone synthesis, signalling and metabolism may, therefore, be responsible for these changes. We have evaluated the correlation between specific genotypes in androgen- and oestrogen-regulating genes (AR, SRD5A2, CYP17 and CYP19), and age-related prostatic changes. METHODS: We have tested genetic susceptibility to morphological and pathological criteria in 195 French Caucasians, using allelic variants for candidate genes involved in androgen/oestrogen prostatic activity: androgen receptor (CAG repeats), 5alpha-reductase type 2 (TA repeats, V89L and A49T mutations), A2 variant of the 17alpha-hydroxylase (CYP17) and the simple tandem repeat polymorphism (STRP) aromatase (CYP19) polymorphisms. RESULTS: The A2 variant of 17alpha-hydroxylase (CYP17) and allele 191 of STRP aromatase (CYP19) showed an opposite effect on age-related prostate hyperplasia: CYP17 being associated with increased risk of prostate enlargement and CYP19 with reduced risk. The 5alpha-reductase type II variants studied did not show links with prostate hyperplasia. The androgen receptor gene CAG repeat length showed a low correlation with the increase of prostate weight, suggesting some effect on age-related prostate growth. CONCLUSION: These results suggested that common variants of the CYP17 gene are associated with prostate enlargement and therefore may increase the risk of development of BPH in this population, while infrequent variants of the aromatase gene (CYP19) could be of a protective nature.

Down-regulation of (IIIb) and (IIIc) isoforms of fibroblast growth factor receptor 2 (FGFR2) is associated with malignant progression in human prostate.

BACKGROUND: Fibroblast growth factors (FGFs) and their receptors (FGFRs) have a critical function in the cellular stroma/epithelium interaction for the development and homeostasis of human prostate. Imbalance in expression of these factors is associated with malignancy in several cancers. METHODS: To quantify the expression of fibroblast growth factor receptor isoforms FGFR2(IIIb), FGFR2(IIIc), FGFR1(IIIc), and fibroblast growth factors FGF2 and FGF7 in normal and tumoral human prostate tissues, and human prostatic epithelial cell lines, we used quantitative real-time polymerase chain reaction. RESULTS: The expression of FGFR2(IIIb) mRNA is down-regulated in 60% of the tumors studied (P < 0.0001). Furthermore, FGFR2(IIIb) is significantly reduced in androgen-independent tumors (AI) compared with androgen-responsive tumors (AD) (P = 0.02). A significant reduction in FGFR2(IIIc) expression is also observed in 80% of tumors (P = 0.001). However, unlike FGFR2(IIIb), the down-regulation of FGFR2(IIIc) is not related to the androgen-independent status (P = 0.09). On the other hand, neither FGFR1(IIIc) nor FGF2 and FGF7 have shown any significant variation in expression between normal and cancerous specimens. CONCLUSIONS: These findings propose that decreased expression of not only FGFR2(IIIb) but also FGFR2(IIIc) isoforms may be a critical step in prostate cancer progression and furthermore suggest that FGFR2(IIIb) expression could be used as a marker for prostate cancer evolution from androgen-dependent to androgen-independent status.

CHC1-L, a candidate gene for prostate carcinogenesis at 13q14.2, is frequently affected by loss of heterozygosity and underexpressed in human prostate cancer.

Loss of heterozygosity (LOH) at chromosome 13q14 is one of the most recurrent anomalies observed in sporadic prostate tumors. This LOH is believed to unmask recessive mutations that inactivate a tumor-suppressor gene(s) which otherwise regulates normal cell growth and suppresses abnormal cell proliferation. Identification of potential tumor-suppressor genes within the deleted region is a way of indicating putative pathways of prostate cancer development and progression. The main target that disappears or is downregulated as a result of 13q14 loss remains to be identified. Therefore, our first concern was to find a gene located in the 13q14 region whose transcription is reduced. CHC1-L, for chromosome condensation 1-like, is mapped to the smallest common deleted region. CHC1-L expression is significantly reduced in prostate tumors compared to normal prostate tissues (p = 0.0002). In 21 of 36 (58%) primary prostate tumors studied, CHC1-L expression was reduced at least 2-fold, as measured by real-time quantitative RT-PCR; 18 of the tumors (50%) showed 13q14 LOH for at least 1 of the 5 polymorphic markers that we studied in the region, and 14 (78%) of these were among the tumors underexpressing CHC1-L. CHC1-L is alternatively spliced at its 5' end to produce 2 isoforms, of 551 and 526 aa. Analyses of CHC1-L integrity and of the quantitative expression of its variants indicate that the observed underexpression in prostate tumors is related to reduced expression of the 551 aa isoform. Although CHC1-L is not the obvious candidate given its only known homology, to RCC1, a guanine nucleotide exchange factor for the Ras-related GTPase Ran, the frequent significant decrease observed in its expression in prostate cancer associated with the difference in frequency of CHC1-L variant isoforms between normal and neoplastic prostate tissues places it in a pivotal role or possibly adjacent to a gene that has that role in prostate cancer evolution.

Targeted screening for prostate cancer in high risk families: early onset is a significant risk factor for disease in first degree relatives.

PURPOSE: Targeted screening for prostate cancer in high risk families is generally suggested by ages 40 to 45 years in first degree relatives. We support this concept by reporting higher risk and earlier onset of the disease in these families. MATERIALS AND METHODS: We proposed serum prostate specific antigen (PSA) testing in 40 to 70-year-old first degree relatives of 435 patients with prostate cancer treated between July 1994 and June 1997. A previous systematic genealogical analysis allowed us to define the familial prostate cancer status of each patient as sporadic or familial. RESULTS: Of the 747 potential candidates 442 (59%) accepted into the study have been screened, including 240 who were 40 to 49 years old (mean age 44.8) and 202 who were 50 to 70 years old (mean age 57.4). Two of the 240 subjects (0.8%) had PSA greater than 4 ng./ml. in the 40 to 49-year-old group. Prostate biopsies were negative in 1 relative but diagnostic for prostate cancer in the other. In the 50 to 70-year-old group 25 of 202 subjects (12.4%) had a PSA of greater than 4 ng./ml. Prostate cancer was diagnosed in 9 individuals (4.5%), 9 had negative biopsy results, 1 died before biopsy and 6 refused biopsy. The proportion of relatives with PSA greater than 4 ng./ml. and prostate cancer detection was not different according to familial status (sporadic or familial) but it was significantly higher in first degree relatives with early onset prostate cancer in the family at ages younger than 65 years (p = 0.037 and 0.012, respectively). CONCLUSIONS: Our results emphasize the usefulness of PSA screening in high risk families, including those without obvious hereditary features. Furthermore, early onset prostate cancer is a significant risk factor for prostate cancer in first degree relatives.

Worry and attitude of men in at-risk families for prostate cancer about genetic susceptibility and genetic testing.

BACKGROUND: The aim of this study was to evaluate worry about genetic susceptibility and the attitude of men with family history of prostate cancer (CaP) toward genetic testing. METHODS: Three hundred seventy-five eligible first-degree relatives (FDR) of men with CaP, were asked to participate in a screening and to fill out a survey covering the worry about genetic susceptibility and interest in genetic testing. RESULTS: Of the 375 candidates contacted, 277 completed the survey, and had undergone PSA measurement. Sixty-four percent worried a little or not at all about inherited predisposition to CaP, while the remainder worried a lot or extremely. The candidates who worried a lot or extremely were men with high levels of durable anxiety disposition (STAI trait), who had undergone a previous screening procedure and men with sons. Ninety-eight percent of men expressed their interest in undergoing genetic testing. The most motivated candidates to have the test done were men with several relatives with CaP. CONCLUSIONS: The level of worry about genetic susceptibility was low and there was a concrete interest in genetic testing in FDR of men with CaP. This interest increased with the number of CaP in the family.