Association of prostate cancer risk variants with clinicopathologic characteristics of the disease

PURPOSE: Fifteen independent genetic variants have been implicated in prostate cancer risk by recent genome-wide association studies. However, their association with clinicopathologic features of prostate cancer is uncertain. EXPERIMENTAL DESIGN: We systematically evaluated these 15 variants in 1,563 prostate cancer patients undergoing radical prostatectomy, taking advantage of the uniform tumor stage and grade information available for each of these cases. Associations of these variants with aggressiveness, pathologic Gleason scores, pathologic stage, age at diagnosis, or serum prostate-specific antigen (PSA) levels were tested. RESULTS: After adjusting for multiple testing, none of the single nucleotide polymorphisms was individually or cumulatively associated with aggressiveness or individual clinicopathologic variables of prostate cancer such as Gleason scores, pathologic stage, or age at diagnosis of prostate cancer. The reported risk allele (G) for single nucleotide polymorphism rs2735839 in the KLK3 gene at 19q13 was more frequent in less aggressive prostate cancer patients (0.89) than in more aggressive prostate cancer patients (0.86; nominal P = 0.03) or in controls (0.86; nominal P = 0.04). Considering that this allele was also significantly associated with higher serum PSA levels among controls (nominal P = 0.003), the observed trend of higher frequency of this risk allele between less and more aggressive prostate cancer, or between less aggressive and controls may be due to detection bias of PSA screening. CONCLUSIONS: Prostate cancer risk variants recently discovered from genome-wide case-control association studies are not associated with clinicopathologic variables in this population. Case-case studies are urgently needed to discover genetic variants that predict tumor aggressiveness.     

The role of metastasis-associated protein 1 in prostate cancer progression

Distinguishing aggressive prostate cancer from indolent disease represents an important clinical challenge, as current therapy requires over treating men with prostate cancer to prevent the progression of a few cases. Expression of the metastasis-associated protein 1 (MTA1) has previously been found to be associated with progression to the metastatic state in various cancers. Analyzing DNA microarray data, we found MTA1 to be selectively overexpressed in metastatic prostate cancer compared with clinically localized prostate cancer and benign prostate tissue. These results were validated by demonstrating overexpression of MTA1 in metastatic prostate cancer by immunoblot analysis. MTA1 protein expression was evaluated by immunohistochemistry in a broad spectrum of prostate tumors with tissue microarrays containing 1940 tissue cores from 300 cases. Metastatic prostate cancer demonstrated significantly higher mean MTA1 protein expression intensity (score = 3.4/4) and percentage of tissue cores staining positive for MTA1 (83%) compared with clinically localized prostate cancer (score = 2.8/4, 63% positive cores) or benign prostate tissue (score = 1.5/4, 25% positive cores) with a mean difference of 0.54 and 1.84, respectively (P < 0.00001 for both). Paradoxically, for localized disease, higher MTA1 protein expression was associated with lower rates of prostate specific antigen recurrence after radical prostatectomy for localized disease. In summary, this study identified an association of MTA1 expression and prostate cancer progression.     

MCM7 amplification and overexpression are associated with prostate cancer progression

The genomic DNA profiles of prostate cancers with aggressive features were compared to the profiles of matched normal DNA to identify genes that are selectively amplified in the cancer cells. One of the identified genes, MCM7, which is a component of the DNA replication licensing complex, has been studied extensively both at the DNA and protein levels in human prostate tissues. Approximately half of the prostate cancer specimens studied showed MCM7 gene amplification, and 60% of the aggressive prostate cancer specimens had increased MCM7 protein expression. Amplification or overexpression of MCM7 was significantly associated with relapse, local invasion and a worse tumor grade. Constitutive expression of MCM7 in a human prostate cancer cell line, DU145, resulted in markedly increased DNA synthesis and cell proliferation compared to vector-only controls, and an increased cell invasion in vitro. Indeed, MCM7 overexpression produced primary tumors 12 times larger than vector-only controls and resulted in a rapid demise of mice bearing those tumors. These studies implicate MCM7, and the DNA replication licensing gene family, in prostate cancer progression, growth and invasion.     

New variants at 10q26 and 15q21 are associated with aggressive prostate cancer in a genome-wide association study from a prostate biopsy screening cohort

Purpose: To identify and examine polymorphisms of genes associated with aggressive and clinical significant forms of prostate cancer among a screening cohort.     Experimental Design: We conducted a genome-wide association study among patients with aggressive forms of prostate cancer and biopsy-proven normal controls ascertained from a prostate cancer screening program. We then examined significant associations of specific polymorphisms among a prostate cancer screened cohort to examine their predictive ability in detecting prostate cancer. Results: We found significant associations between aggressive prostate cancer and five single nucleotide polymorphisms (SNPs) in the 10q26 (rs10788165, rs10749408, and rs10788165, p value for association 1.3 × 10⁻¹⁰ to 3.2 × 10⁻¹¹) and 15q21 (rs4775302 and rs1994198, p values for association 3.1 × 10⁻⁸ to 8.2 × 10⁻⁹) regions. Results of a replication study done in 3439 patients undergoing a prostate biopsy, revealed certain combinations of these SNPs to be significantly associated not only with prostate cancer but with aggressive forms of prostate cancer using an established classification criterion for prostate cancer progression (odds ratios for intermediate to high-risk disease 1.8–3.0, p value 0.003–0.001). These SNP combinations were also important clinical predictors for prostate cancer detection based on nomogram analysis that assesses prostate cancer risk. Conclusions: Five SNPs were found to be associated with aggressive forms of prostate cancer. We demonstrated potential clinical applications of these associations.     

Obesity and survival after radical prostatectomy: A 10-year prospective cohort study

BACKGROUND: Obesity and prostate cancer are among the most common health problems affecting American men today. The authors' goal was to assess the impact of obesity on clinical and pathologic features of prostate cancer and long-term outcomes. METHODS: The authors performed a prospective cohort study on 5313 men who underwent radical prostatectomy between 1990 and 1999. Patient height and weight were measured at the time of surgery to calculate the body mass index (BMI). The patients were separated into 3 BMI groups: BMI <25, 25-29.9, and > or =30 kg/m2. The associations between BMI and age, prostate-specific antigen (PSA) level, and Gleason score were assessed with the Spearman rank correlation test. The associations between BMI and pathologic features were assessed with the Mantel-Haenszel chi 2 test. Fifteen-year biochemical progression-free survival, systemic progression-free survival, cancer-specific survival, and overall survival were estimated using the Kaplan-Meier method and evaluated using Cox models. RESULTS.: The median length of follow-up for the entire cohort was 10.1 years. Clinical and pathologic features appear worse in patients with a higher BMI. On univariate and multivariate analyses, it was found that BMI had no impact on biochemical progression, systemic progression, prostate cancer survival, or overall survival. CONCLUSIONS: Obese patients appear to have worse pathologic features at the time of prostatectomy. Despite these features, long-term oncologic outcomes, including cancer-specific survival, remain the same regardless of BMI. BMI appears to influence prostate cancer outcomes at the time of prostatectomy, as evidenced by more aggressive pathologic features. However, after prostatectomy, BMI does not appear to be an independent predictor of recurrence or survival.     

Multiple genes in human 20q13 chromosomal region are involved in an advanced prostate cancer xenograft

We analyzed a prostate cancer xenograft derived from a locally advanced tumor using combined cytogenetic, array-based comparative genomic hybridization and expression analyses. This analysis revealed that genes in the 20q13 chromosomal region, CSE1L, ZNF217, MYBL2, and STK15, were significantly overexpressed in this tumor. The expression pattern of these genes was then confirmed in two large human prostate cancer microarray databases. Furthermore, the MYBL2 and STK15 have been significantly overexpressed in prostate metastases, allowing a clear distinction between localized tumors and metastases. Our data suggest these genes to be involved in advanced stages of prostate tumorigenesis and as such, they may serve as markers for tumor progression.     

Hormone therapy failure in human prostate cancer: analysis by complementary DNA and tissue microarrays.

BACKGROUND: The molecular mechanisms underlying the progression of prostate cancer during hormonal therapy have remained poorly understood. In this study, we developed a new strategy for the identification of differentially expressed genes in hormone-refractory human prostate cancer by use of a combination of complementary DNA (cDNA) and tissue microarray technologies. METHODS: Differences in gene expression between hormone-refractory CWR22R prostate cancer xenografts (human prostate cancer transplanted into nude mice) and a xenograft of the parental, hormone-sensitive CWR22 strain were analyzed by use of cDNA microarray technology. To validate the data from cDNA microarrays on clinical prostate cancer specimens, a tissue microarray of specimens from 26 prostates with benign prostatic hyperplasia, 208 primary prostate cancers, and 30 hormone-refractory local recurrences was constructed and used for immunohistochemical detection of protein expression. RESULTS: Among 5184 genes surveyed with cDNA microarray technology, expression of 37 (0.7%) was increased more than twofold in the hormone-refractory CWR22R xenografts compared with the CWR22 xenograft; expression of 135 (2.6%) genes was reduced by more than 50%. The genes encoding insulin-like growth factor-binding protein 2 (IGFBP2) and 27-kd heat-shock protein (HSP27) were among the most consistently overexpressed genes in the CWR22R tumors. Immunohistochemical analysis of tissue microarrays demonstrated high expression of IGFBP2 protein in 100% of the hormone-refractory clinical tumors, in 36% of the primary tumors, and in 0% of the benign prostatic specimens (two-sided P =.0001). Overexpression of HSP27 protein was demonstrated in 31% of the hormone-refractory tumors, in 5% of the primary tumors, and in 0% of the benign prostatic specimens (two-sided P =.0001). CONCLUSIONS: The combination of cDNA and tissue microarray technologies enables rapid identification of genes associated with progression of prostate cancer to the hormone-refractory state and may facilitate analysis of the role of the encoded gene products in the pathogenesis of human prostate cancer.     

Methylation in benign prostate and risk of disease progression in men subsequently diagnosed with prostate cancer

In DNA from prostate tumors, methylation patterns in gene promoter regions can be a biomarker for disease progression. It remains unclear whether methylation patterns in benign prostate tissue—prior to malignant transformation—may provide similar prognostic information. To determine whether early methylation events predict prostate cancer outcomes, we evaluated histologically benign prostate specimens from 353 men who eventually developed prostate cancer and received “definitive” treatment [radical prostatectomy (58%) or radiation therapy (42%)]. Cases were drawn from a large hospital‐based cohort of men with benign prostate biopsy specimens collected between 1990 and 2002. Risk of disease progression associated with methylation was estimated using time‐to‐event analyses. Average follow‐up was over 5 years; biochemical recurrence (BCR) occurred in 91 cases (26%). In White men, methylation of the APC gene was associated with increased risk of BCR, even after adjusting for standard clinical risk factors for prostate cancer progression (adjusted hazard ratio (aHR) = 2.26; 95%CI 1.23–4.16). APC methylation was most strongly associated with a significant increased risk of BCR in White men with low prostate specific antigen at cohort entry (HR = 3.66; 95%CI 1.51–8.85). In additional stratified analyses, we found that methylation of the RARB gene significantly increased risk of BCR in African American cases who demonstrated methylation of at least one of the other four genes under study (HR = 3.80; 95%CI 1.07–13.53). These findings may have implications in the early identification of aggressive prostate cancer as well as reducing unnecessary medical procedures and emotional distress for men who present with markers of indolent disease.     

A prospective study of trans-fatty acid levels in blood and risk of prostate cancer.

BACKGROUND: Previous studies suggest a positive association between markers of trans-fatty acid intake and prostate cancer. We therefore prospectively evaluated the association between blood trans-fatty acid levels and risk of prostate cancer. METHODS: We conducted a nested case-control study among 14,916 apparently healthy men who provided blood samples in 1982. Blood fatty acid levels were determined for 476 men diagnosed with prostate cancer during a 13-year follow-up and their matched controls. Controls were individually matched to cases according to age and smoking status at baseline. Conditional logistic regression was used to estimate the relative risk and 95% confidence interval of total, nonaggressive (stage A/B and low grade), and aggressive (stage C/D, high grade, subsequent distant metastasis or death) prostate cancer associated with blood levels of specific trans-fatty acids. RESULTS: Blood levels of all the trans-fatty acids examined were unrelated to total prostate cancer risk. When results were divided according to tumor aggressiveness, blood levels of 18:1n-9t, all the 18:2t examined, and total trans-fatty acids were positively associated to nonaggressive tumors. The relative risks (95% confidence intervals; P trend) comparing top with bottom quintile trans-fatty acid levels were 2.16 (1.12-4.17; 0.11) for 18:1n-9t, 1.97 (1.03-3.75; 0.01) for total 18:2t, and 2.21 (1.14-4.29; 0.06) for total trans-fatty acids. None of the trans fats examined was associated with aggressive prostate tumors. CONCLUSION: Blood levels of trans isomers of oleic and linoleic acids are associated with an increased risk of nonaggressive prostate tumors. As this type of tumors represents a large proportion of prostate cancer detected using prostate-specific antigen screening, these findings may have implications for the prevention of prostate cancer.     

Gene variants in the angiogenesis pathway and prostate cancer

Although the causes of prostate cancer are still unknown, numerous studies support the role of genetic factors in the development and progression of this disease. Single nucleotide polymorphisms (SNPs) in key angiogenesis genes have been studied in prostate cancer. In this review, we provide an overview of the current knowledge of the role of genetic variants in the angiogenesis pathway in prostate cancer risk and progression. Of the 17 prostate cancer genome-wide association studies (GWAS) conducted to date, only one identified disease-associated SNPs in a region of an angiogenesis pathway gene. An association was observed between aggressive disease and three intergenic SNPs (rs11199874, rs10749408 and rs10788165) in a region on chromosome 10q26 that encompasses FGFR2. The majority (27/32, 84.4%) of primary candidate gene studies reviewed had a small (n < 800, 20/32, 62.5%) to medium sample size (n = 800-2000, 7/32, 21.9%), whereas only five (15.6%) had a large sample size (n ≥ 2000). Results from the large studies revealed associations with risk and aggressive disease for SNPs in NOS2A, NOS3 and MMP-2 and risk for HIF1-α. Meta-analyses have so far been conducted on FGFR2, TGF-β, TNF-α, HIF1-α and IL10 and the results reveal an association with risk for SNPs in FGFR2 and TGF-β and aggressive disease for SNPs in IL-10. Thus, existing evidence from GWAS and large candidate gene studies indicates that SNPs from a limited number of angiogenesis pathway genes are associated with prostate cancer risk and progression.     

Patterns in metabolite profile are associated with risk of more aggressive prostate cancer: A prospective study of 3,057 matched case–control sets from EPIC

Metabolomics may reveal novel insights into the etiology of prostate cancer, for which few risk factors are established. We investigated the association between patterns in baseline plasma metabolite profile and subsequent prostate cancer risk, using data from 3,057 matched case–control sets from the European Prospective Investigation into Cancer and Nutrition (EPIC). We measured 119 metabolite concentrations in plasma samples, collected on average 9.4 years before diagnosis, by mass spectrometry (AbsoluteIDQ p180 Kit, Biocrates Life Sciences AG). Metabolite patterns were identified using treelet transform, a statistical method for identification of groups of correlated metabolites. Associations of metabolite patterns with prostate cancer risk (OR_1SD) were estimated by conditional logistic regression. Supplementary analyses were conducted for metabolite patterns derived using principal component analysis and for individual metabolites. Men with metabolite profiles characterized by higher concentrations of either phosphatidylcholines or hydroxysphingomyelins (OR_1SD = 0.77, 95% confidence interval 0.66–0.89), acylcarnitines C18:1 and C18:2, glutamate, ornithine and taurine (OR_1SD = 0.72, 0.57–0.90), or lysophosphatidylcholines (OR_1SD = 0.81, 0.69–0.95) had lower risk of advanced stage prostate cancer at diagnosis, with no evidence of heterogeneity by follow-up time. Similar associations were observed for the two former patterns with aggressive disease risk (the more aggressive subset of advanced stage), while the latter pattern was inversely related to risk of prostate cancer death (OR_1SD = 0.77, 0.61–0.96). No associations were observed for prostate cancer overall or less aggressive tumor subtypes. In conclusion, metabolite patterns may be related to lower risk of more aggressive prostate tumors and prostate cancer death, and might be relevant to etiology of advanced stage prostate cancer.     

Clinical validation of candidate genes associated with prostate cancer progression in the CWR22 model system using tissue microarrays

To explore molecular mechanisms of prostate cancer progression, we applied tissue microarrays (TMAs) to analyze expression of candidate gene targets discovered by cDNA microarray analysis of the CWR22 xenograft model system. A TMA with 544 clinical specimens from different stages of disease progression was probed by mRNA in situ hybridization and protein immunohistochemistry. There was an excellent correlation (r = 0.96; n = 16) between the expression levels of the genes in the xenografts by cDNA microarray and mRNA in situ hybridization on a TMA. One of the most highly overexpressed genes in hormone-refractory CWR22R xenografts was the S100P gene. This gene, coding for a calcium signaling molecule implicated in the loss of senescence, was also significantly associated with progression in clinical tumors by TMA analysis (P < 0.001), suggesting dysregulation of this pathway in hormone-refractory and metastatic prostate cancers. Conversely, two genes that were down-regulated during tumor progression in the CWR22 model system were validated in vivo: crystallin mu (CRYM) and a LIM-domain protein LMO4 both showed significantly lower mRNA levels in hormone-refractory tumors as compared with primary tumors (P < 0.001). These results illustrate a strategy for rapid clinical validation at the mRNA and protein level of gene targets found to be differentially expressed in cDNA microarray experiments of model systems of cancer.     

Molecular features of hormone-refractory prostate cancer cells by genome-wide gene expression profiles

One of the most critical issues in prostate cancer clinic is emerging hormone-refractory prostate cancers (HRPCs) and their management. Prostate cancer is usually androgen dependent and responds well to androgen ablation therapy. However, at a certain stage, they eventually acquire androgen-independent and more aggressive phenotype and show poor response to any anticancer therapies. To characterize the molecular features of clinical HRPCs, we analyzed gene expression profiles of 25 clinical HRPCs and 10 hormone-sensitive prostate cancers (HSPCs) by genome-wide cDNA microarrays combining with laser microbeam microdissection. An unsupervised hierarchical clustering analysis clearly distinguished expression patterns of HRPC cells from those of HSPC cells. In addition, primary and metastatic HRPCs from three patients were closely clustered regardless of metastatic organs. A supervised analysis and permutation test identified 36 up-regulated genes and 70 down-regulated genes in HRPCs compared with HSPCs (average fold difference > 1.5; P < 0.0001). We observed overexpression of AR, ANLN, and SNRPE and down-regulation of NR4A1, CYP27A1, and HLA-A antigen in HRPC progression. AR overexpression is likely to play a central role of hormone-refractory phenotype, and other genes we identified were considered to be related to more aggressive phenotype of clinical HRPCs, and in fact, knockdown of these overexpressing genes by small interfering RNA resulted in drastic attenuation of prostate cancer cell viability. Our microarray analysis of HRPC cells should provide useful information to understand the molecular mechanism of HRPC progression and to identify molecular targets for development of HRPC treatment.     

Expression profiling reveals hepsin overexpression in prostate cancer

Prostate cancer is the most commonly diagnosed noncutaneous cancer in men. Despite this fact, many of the genetic changes that coincide with prostate cancer progression remain enigmatic. We have addressed this problem by characterizing the expression profiles of several benign and malignant human prostate samples, and we have identified several genes that are differentially expressed between benign and malignant glands. One gene that was overexpressed encodes the serine protease hepsin. We used an independent sample set to confirm that hepsin is overexpressed in prostate tumors, and in situ hybridization demonstrates that hepsin is specifically overexpressed in the carcinoma cells themselves. These facts, together with the molecular properties of hepsin, make it an ideal target for prostate cancer therapy.     

Smoking and aggressive prostate cancer: a review of the epidemiologic evidence

Although tobacco use has been recognized as one of the leading causes of cancer morbidity and mortality, a role of smoking in the occurrence of prostate cancer has not been established. However, evidence indicates that factors that influence the incidence of prostate cancer may differ from those that influence progression and fatality from the disease. Thus, we reviewed and summarized results from prospective cohort studies that assessed the relation between smoking and fatal prostate cancer risk, as well as epidemiological and clinical studies that focused on aggressive behavior in prostate cancer, such as poorer survival, advanced stage, or poorer differentiation at diagnosis. The majority of the prospective cohort studies showed that current smoking is associated with a moderate increase of ~30% in fatal prostate cancer risk compared to never/non-smokers. This association is likely to be an underestimate of the effect of smoking because most studies had a single assessment of smoking at baseline and long follow-up times, and the association was considerably stronger in some sub-groups of heaviest smokers, or when smoking was assessed in a relatively short period (within 10 years) prior to cancer mortality. Using aggressive behavior of prostate cancer as outcome, current smoking was associated with significantly elevated risk, ranging from around twofold to threefold or higher. Although alternative explanations, such as publication bias, residual confounding, screening bias, and the influence of smoking-related comorbidities cannot be ruled out entirely, these findings suggest that smoking is associated with aggressive behavior of prostate cancers or with a sub-group of rapidly progressing prostate cancer. Based on evidence presented in this review, cigarette smoking is likely to be a risk factor for prostate cancer progression and should be considered as a relevant exposure in prostate cancer research and prevention of mortality from this cancer.     

Survivin expression is associated with features of biologically aggressive prostate carcinoma

BACKGROUND: Survivin counteracts cell death and controls mitotic progression. The objectives of the current study were to compare the expression patterns of survivin in normal prostate, primary prostate carcinoma, and lymph node tissues involved with prostate carcinoma and to determine whether the expression of survivin is associated with prostate carcinoma characteristics and progression. METHODS: Immunohistochemical staining for survivin and for transforming growth factor beta1 (TGF-beta1) and its receptors (types I and II; TGF-betaR1 and TGF-betaR2, respectively) was carried out on archival specimens from 114 consecutive patients who underwent radical prostatectomy (median follow-up, 64.8 months). Punch biopsies of the index carcinoma and normal tissue from each specimen were sectioned onto a single slide and stained. The authors also evaluated the expression of survivin in normal and malignant lymph node tissue from eight patients. RESULTS: Survivin was expressed in 41 of 114 normal prostate specimens (36%) from prostates that contained carcinoma, in 81 of 114 primary prostate carcinoma specimens (71%), in 3 of 8 normal lymphoid specimens (38%), and in 7 of 8 prostate carcinoma lymphoid specimens (88%). Survivin expression was associated with higher final Gleason sum (P = 0.001), loss of TGF-betaR1 and TGF-betaR2 expression (P = 0.041 and P = 0.008, respectively), and an increased risk of biochemical progression on univariate analysis (P = 0.0441). Among patients who had disease progression, survivin was expressed more commonly in those who had tumors with features of aggressive behavior. CONCLUSIONS: The expression of survivin gradually increased from normal prostate tissue, to low-grade primary carcinoma, to high-grade primary carcinoma and was highest in lymph node metastases. Survivin expression was associated further with alteration of the TGF-beta pathway and with overall and aggressive biochemical progression after radical prostatectomy.     

Circadian genes and risk of prostate cancer: Findings from the EPICAP study

Circadian rhythms regulate several physiological functions and genes controlling the circadian rhythm were found to regulate cell proliferation, cell cycle and apoptosis. Few studies have investigated the role of those circadian genes in prostate cancer occurrence. We aim to investigate the relationship between circadian genes polymorphisms and prostate cancer risk based on data from the EPICAP study, a population-based case–control study including 1,515 men (732 cases / 783 controls) with genotyped data. Odds Ratios (ORs) for association between prostate cancer and circadian gene variants were estimated for each of the 872 single nucleotide polymorphisms (SNPs) in 31 circadian clock genes. We also used a gene-based and pathway-based approach with a focus on the pathway including 9 core circadian genes. Separate analyses were conducted by prostate cancer aggressiveness. The core-circadian pathway (p = 0.0006) was significantly associated to prostate cancer, for either low (p = 0.002) or high (p = 0.01) grade tumor. At the gene level, we observed significant associations between all prostate cancer and NPAS2 and PER1 after correcting for multiple testing, while only RORA was significant for aggressive tumors. At the SNP-level, no significant association was observed. Our findings provide additional evidence of a potential link between genetic variants in circadian genes and prostate cancer risk. Further investigation is warranted to confirm these findings and to better understand the biological pathways involved.     

A gain of function TGFB1 polymorphism may be associated with late stage prostate cancer.

Transforming growth factor beta (TGFbeta) is known to exert both positive and negative effects on different stages of tumor formation. Of the TGFbetaisoforms, TGFbeta1 is highly expressed in prostate cancer and leads to tumor promotion and metastasis. Increased expression of TGFbeta1 is associated with more aggressive tumors and poor prognosis. Several polymorphisms in TGFB1 have been identified, and two variants in strong linkage disequilibrium, C-509T and T+29C, show increased serum levels. Because of the potential role of TGFB1 variants in prostate cancer and progression, we hypothesized that these two TGFB1 variants would be associated with prostate cancer risk, particularly later, more aggressive stage tumors. To test this, we conducted a nested case-control study of 492 men diagnosed with prostate cancer from the Physicians Health Study and 492 age-matched controls. In this study, cases who were homozygous for the T allele at position -509 had a 2.4-fold increased risk of more advanced stage of prostate cancer [95% confidence interval (95% CI) 1.03-5.43; P = 0.04]. The T allele frequencies in cases and controls were 32.7% and 31.4%, respectively. The same polymorphism showed a 1.23 nonsignificant odds ratio (OR) for overall prostate cancer risk (95% CI 0.80-1.87). Cases who were homozygous for the C allele at position +29 did not show any significant increase in risk for either total prostate cancer (OR 1.19, 95% CI 0.82-1.74) or advanced stage prostate cancer (OR 1.33, 95% CI 0.66-2.68). The C allele frequency in cases and controls were 39.9% and 38.5%, respectively. Our data suggest that the TGFB1 C-509T variant that affects expression of TGFbeta1 may play a role in advanced stage prostate cancer.     

Molecular profiling in prostate cancer

Prostate cancer is the most diagnosed cancer and the second leading cause of cancer death among men in the United States. Ability to detect this cancer early and availability of better prognostic markers are critical in order to decrease morbidity and mortality of prostate cancer. With the recent development in gene expression analysis methodology, expression profiles of thousands of genes can be generated in tissue samples and cell lines. Comparison of the global gene expression patterns between normal prostate and tumors at different stages may allow us to understand better the molecular mechanism of prostate tumorigenesis and progression. Different cancer cell lines and tissues appear to have different gene expression patterns that provide a new tool to classify tumors. Molecular classification of prostate cancer holds great promise for early detection and prognosis of this disease in the future. In this review, we summarize some of the recent mRNA and protein expression profiling studies performed in prostate cancer. Further, we discuss the potential benefits and limitations of current profiling technology.