HSD17B4 overexpression, an independent biomarker of poor patient outcome in prostate cancer.

Steroid hormones and their metabolising enzymes have been studied extensively for their potential role in prostate cancer, with more recent interest in the androgen/estrogen inactivating enzyme 17beta-hydroxysteroid dehydrogenase type 4 (HSD17B4). Gene expression profiling showed HSD17B4 to be significantly overexpressed in prostate cancer compared to matched-benign epithelium. We therefore hypothesized that altered HSD17B4 expression may contribute to prostate cancer progression via altered hormone balance. In this study, HSD17B4 mRNA and protein expression were assessed by in situ hybridisation (ISH) and immunohistochemistry (IHC), respectively, in tissue arrays of prostate tissue from 172 patients treated by radical prostatectomy. Overexpression of HSD17B4 mRNA and protein was associated with prostate cancer (P<0.0001) and multivariate Cox proportional hazards analysis, adjusted for known prognostic indicators, demonstrated HSD17B4 mRNA and high protein expression were significant independent predictors of poor patient outcome as measured by time until PSA relapse (mRNA: hazards ratio [HR]=1.90, 95% confidence interval [CI]=1.15-3.12; P<0.0001; and protein: HR=2.09, 95% CI=1.31-3.33; P=0.0026). Here we provide strong evidence that both mRNA and protein overexpression of HSD17B4 is not only associated with the presence of prostate cancer, but is also a significant independent predictor of poor patient outcome.

No association between common chemokine and chemokine receptor gene variants and prostate cancer risk.

There is growing evidence that inflammation and infection play important roles in the etiology of prostate cancer. As the chemokine network is directly involved in inflammation and infectious diseases, we tested for an association between six common putative functional variants and prostate cancer risk using an Australian case-control study. We measured CCL5 -403G>A, CXCL12 +801G>A, CCR2V64I (G>A), CCR5Delta32, CX3CR1V249I (G>A), and CX3CR1T280M (C>T) for 815 cases and 738 controls. Of these, only CXCL12 +801G>A has previously been tested and found to be associated with prostate cancer risk. We found no significant associations with prostate cancer risk (all P > 0.4). All per allele odds ratios ranged from 0.96 (95% confidence intervals, 0.80-1.16) to 1.06 (95% confidence intervals, 0.90-1.23). This suggests that these common chemokine and chemokine receptor variants do not play a major, if any, role in susceptibility to prostate cancer.

The rs743572 common variant in the promoter of CYP17A1 is not associated with prostate cancer risk or circulating hormonal levels.

OBJECTIVE: To use a large population-based case-control study to test the association between the common genetic variant rs743572 (-34 T to C), prostate cancer risk and circulating levels of several hormones. SUBJECTS AND METHODS: A previous meta-analysis concluded that reported associations between rs743572 in the promoter of CYP17A1 and prostate cancer risk might reflect publication bias, but a few recent studies reported associations with prostate cancer risk and data suggesting that rs743572 is functional. We genotyped 824 prostate cancer cases and 737 population-based controls, and applied unconditional logistic regression to estimate the association between rs743572 and prostate cancer risk. We also used linear regression of transformed testosterone, androstanediol glucuronide, dehydroepiandrosterone sulphate, androstenedione, sex hormone-binding globulin and oestradiol (circulating levels) measured for controls, to estimate the association between these levels and rs743572. The linear models were adjusted for age and laboratory batch. RESULTS: Men with different genotypes had similar circulating levels of all the hormones measured (all P < 0.05). In the case-control comparison using unconditional unadjusted logistic regression, the odds ratios (95% confidence interval) for prostate cancer were 1.07 (0.87-1.32) and 0.94 (0.71-1.25) for the dominant and recessive models, respectively, and for the co-dominant model, 1.10 (0.88-1.36) and 0.99 (0.73-1.35) for carriers of one or two copies of the C allele, respectively. There was no evidence of heterogeneity in the odds ratios by tumour stage (all P > 0.3) and grade (all P > 0.3). CONCLUSION: The results of the present study are consistent with the conclusions of the previous meta-analysis, and suggest that rs743572 has no role in the risk of prostate cancer for men of Caucasian origin.

Mammographic density and candidate gene variants: a twins and sisters study.

BACKGROUND: Mammographic density, the light/white radiographic appearance on a mammogram that represents connective and epithelial tissue, is a strong risk factor for breast cancer which seems to be highly heritable. Little is known about its genetic determinants. METHODS: We studied 457 women from 207 sisterhoods (104 monozygotic twins, 182 dizygotic twins, and 171 singletons). Percentage mammographic density (PMD) as well as dense area and nondense area were calculated using a computer-assisted method. We measured six single nucleotide polymorphisms from six candidate genes (COMT, HSD3B1, IGFBP3, HER2, XPD, and XRCC3). Associations between genotypes and mammographic measures were tested (a) cross-sectionally using a multivariate normal model fitted using FISHER that allowed separate correlations for monozygotic, dizygotic, and nontwin pairs and (b) within sister pairs using paired t tests. RESULTS: Cross-sectionally, each additional copy of the HSD3B1 Asn(367)Thr variant allele was associated with lower PMD (-3.47% per allele; SE = 1.65; P = 0.035). Within-pair regression estimates confirmed this association. There was no evidence for an association between the mammographic density measures and any of the other variants studied. CONCLUSION: We have replicated an association between a variant in the HSD3B1 gene and PMD, which suggests that HSD3B1 may be genetic determinant of mammographic density.

The common variant rs1447295 on chromosome 8q24 and prostate cancer risk: results from an Australian population-based case-control study.

A recent study from deCode reported an association between common variants in the region 8q24 and prostate cancer risk. The strongest association was found with the single nucleotide polymorphism rs1447295. We genotyped 821 prostate cancer cases and 732 population controls for rs1447295 to test the association between this common variant and prostate cancer risk, and examine whether this association depends on Gleason score. Our case-control study confirmed the association between rs1447295 and prostate cancer risk (P = 0.0005). The odds ratio (OR) for prostate cancer was 1.52 [95% confidence interval (CI), 1.20-1.93] for carriers of any A allele compared with noncarriers. The OR for Gleason score 5 to 6 prostate cancer (1.48; 95% CI, 1.13-1.95) was similar to the OR for Gleason score 7 to 10 prostate cancer (1.58; 95% CI, 1.18-2.11, P for heterogeneity = 0.7). We conclude that the A allele of rs1447295 is associated with a higher risk of prostate cancer regardless of tumor aggressiveness, suggesting that such a variant, or a variant in linkage disequilibrium with it, plays a role early in prostate carcinogenesis.

5alpha-Reductase type 2 gene variant associations with prostate cancer risk, circulating hormone levels and androgenetic alopecia.

Controversy exists over the significance of associations between the SRD5A2 (5alpha-reductase type 2) polymorphisms, A49T and V89L, and risk of prostate cancer. These potentially functional polymorphisms may alter life-long exposure to androgens with subsequent effects on male health and aging. The aim of this study was to examine the association of these variants with prostate cancer risk, plasma hormone levels and androgenetic alopecia. Subjects include 827 cases and 736 controls from an Australian population-based case-control study of prostate cancer. Information on prostate cancer risk factors and patterns of balding were collected. Plasma levels of testosterone, 3alpha-diol glucuronide (3alpha-diolG), dehydroepiandrosterone sulfate, androstenedione, sex hormone-binding globulin and estradiol were measured for controls. No associations with the V89L polymorphism were found. Carriers of the rarer A49T A allele were at a 60% higher risk of prostate cancer (OR = 1.60; 95% CI 1.09-2.36; p = 0.02) and 50% lower risk of vertex and frontal balding (p = 0.03) compared with men homozygous for the more common G allele. Although we found little evidence of association between this variant and plasma levels of 5 measured androgens, circulating 3alpha-diolG levels were 34% lower in A49T A allele carriers (p < 0.0001). Our study provides evidence that the SRD5A2 A49T A variant is associated with an increased risk of prostate cancer, lower levels of circulating 3alpha-diolG and decreased risk of baldness. These findings raise important questions with respect to previous assumptions concerning hormonal influences on prostate cancer risk in ageing males.

Variants in the prostate-specific antigen (PSA) gene and prostate cancer risk, survival, and circulating PSA.

An A to G substitution, rs925013, in the promoter of the prostate-specific antigen gene (PSA) was recently found to be associated with promoter activity and circulating PSA levels. The objective of this study was to test the associations between rs925013 and another A to G substitution, rs266882, in the PSA gene with prostate cancer risk using a population-based case-control study of 821 prostate cancer cases and 734 controls carried out in Perth and Melbourne, Australia. The study focused on young (i.e., < 70 years) and aggressive cases (i.e., well-differentiated tumors were excluded). Cases in the Melbourne arm of the study (N = 638) were followed up prospectively for an average period of 8.2 years and deaths from prostate cancer ascertained through record linkage to study the possible association between genetic variants and disease-specific survival. PSA-circulating levels were measured in controls to test the association with the genetic variants using a cross-sectional design. Linear regression of log PSA levels, unconditional logistic regression, Cox regression, and haplotype analyses were undertaken. For rs925013, the G allele was associated with an increased risk of prostate cancer [odds ratio, 1.4; 95% confidence interval (95% CI), 1.1-1.7; P = 0.001], and the hazard ratio for survival for cases homozygous for the G allele compared with cases homozygous for the A allele was increased but not statistically significant (hazard ratio, 2.3; 95% CI, 1-5.6; P = 0.06). For rs266882, there was no association with overall prostate cancer risk and survival (all P > 0.1). Men homozygous or heterozygous for the G/G (rs925013/rs266882) haplotype were at higher risk of prostate cancer than men homozygous for the A/A haplotype (odds ratio, 1.3; 95% CI, 1.1-1.7; P = 0.009). Adjusted geometric means of circulating PSA levels in controls were similar in men with zero, one, and two copies of the G allele in rs266882 (1.2, 1.1, and 1.3 ng/mL, respectively; all P > or = 0.2) and rs925013 (1.1, 1.2, and 1.5 ng/mL, respectively; all P > 0.1). For rs925013, our study provides good evidence of association with prostate cancer risk, marginal evidence of association with survival, and little evidence of detectable association with circulating PSA levels in controls. We found no evidence of an independent association between rs266882 and any of the outcomes. The genotypes and haplotypes studied might be associated with the PSA gene function or be in linkage disequilibrium with other unmeasured and functional variants in the PSA or other genes.

Macrophage inhibitory cytokine-1 H6D polymorphism, prostate cancer risk, and survival.

Macrophage inhibitory cytokine-1 (MIC-1), a member of the transforming growth factor-beta superfamily, is important in regulating inflammation. Inflammation of the prostate has been suggested to favor tumor development. A recent study (JNCI 2004, 96:1248-1254) found marginal evidence of an association between the presence of the mature MIC-1 protein nonsynonymous polymorphism H6D C-to-G (rs1058587) with reduced prostate cancer risk [odds ratio, 0.83; 95% confidence interval (95% CI), 0.69-0.99]. We tested this in a population-based study of 819 cases and 731 controls from Australia and found a similar, yet not significant, odds ratio of 0.85 (95% CI, 0.7-1.04; P = 0.11). We also tested the potential association between the H6D variant and disease-specific survival in 640 cases followed-up for an average of 8.2 years. We found that cases carrying the H6D G allele had an increased risk of death from prostate cancer than cases carrying two copies of the C allele (hazard ratio, 1.72; 95% CI, 1.06-2.78; P = 0.03). Our data suggest that the H6D variant in MIC-1 might play a role in prostate cancer, but it is difficult to explain how a variant can be associated with lower risk of developing prostate cancer but more aggressive growth if cancer develops.

The E211 G>A androgen receptor polymorphism is associated with a decreased risk of metastatic prostate cancer and androgenetic alopecia.

The androgen receptor (AR) gene encodes a transcription factor, which mediates androgen action in target tissues, including the prostate. Prostate cancer is androgen dependent, implicating AR in susceptibility to this male condition. Male pattern balding, androgenetic alopecia, has recently been associated with prostate cancer, suggesting shared androgen pathways. The CAG and GGC repeats in the AR have been studied extensively as markers of prostate cancer susceptibility, with inconclusive findings, whereas the AR-E211 G>A polymorphism has been associated with androgenetic alopecia. We assessed the repeat linked single nucleotide polymorphism as a marker of risk association in prostate cancer, including androgenetic alopecia, in an Australian population-based case-control study. In 815 prostate cancer cases and 719 controls, the proportion of A-allele carriers was the same in each group. Overall, there was no evidence for an association between the A allele and risk of prostate cancer, however, the proportion of A-allele carriers in metastatic prostate cancer (5%) was lower than in less advanced disease (16%, P = 0.03). The proportion of A-allele carriers was 24% in nonbald men but it was lower in men with vertex alopecia alone (13%, P = 0.001) or in combination with frontal alopecia (7%, P < 0.0001). This inverse association between the A allele and baldness was independent of prostate cancer status (P for interaction = 0.2). These results suggest that the AR-E211 A allele, in linkage with the functional repeat sequences, is associated with a lower risk of metastatic prostate cancer and a lower risk of alopecia.

Genetic variants in the vitamin D receptor gene and prostate cancer risk.

Vitamin D receptor (VDR), a member of the steroid/thyroid hormone nuclear receptor family, is bound by the steroid hormone 1,25-dihydroxyvitamin D3, which is thought to play a role in the etiology and progression of prostate cancer. Polymorphisms in the VDR gene have been associated with prostate cancer risk, although findings are inconclusive. The purpose of this study was to determine if VDR polymorphisms were associated with prostate cancer risk using a large, Australian population-based study of 812 cases and 713 controls frequency-matched by age. As the 3' region polymorphisms are in strong linkage disequilibrium, for joint effects, we only evaluated the common g.60890G > A polymorphism with the unlinked g.27823C > T (5' region) polymorphism. Allele frequencies were similar in cases and controls (g.27823C > T, 36% versus 36%; g.60890 G>A, 41% versus 43%). No genotypes were individually associated with prostate cancer risk (all P > 0.3). All nine possible genotype combinations were evident, and although the g.27823CT/g.60890GA combination was nominally more prevalent in controls (24%) than in cases (19%, P = 0.03), there was no difference in the combined genotype distribution between cases and controls (P = 0.2). The associations of risk with genotype were between 0.91 and 1.03, all with 95% confidence intervals within 0.81 to 1.15. In conclusion, VDR polymorphisms either alone or in combination do not seem to contribute appreciably to prostate cancer risk.