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.

The propeptide mediates formation of stromal stores of PROMIC-1: role in determining prostate cancer outcome.

The extracellular matrix (ECM) is a reservoir of cellular binding proteins and growth factors that are critical for normal cell behavior, and aberrations in the ECM invariably accompany malignancies such as prostate cancer. Carcinomas commonly overexpress macrophage inhibitory cytokine 1 (MIC-1), a proapoptotic and antitumorigenic transforming growth factor-beta superfamily cytokine. Here we show that MIC-1 is often secreted in an unprocessed propeptide containing form. It is variably processed intracellularly, with unprocessed forms being secreted from several tumor lines, including prostate carcinoma lines, PC-3 and LNCaP. Once secreted, only unprocessed proMIC-1 binds ECM, demonstrating for the first time the occurrence of extracellular stores of MIC-1. The propeptide mediates this association via its COOH-terminal 89 amino acids. Xenograft models bearing tumors secreting various engineered forms of MIC-1 show that the propeptide regulates the balance between ECM stores and circulating serum levels of mature MIC-1 in vivo. The absence of propeptide results in approximately 20-fold increase in serum MIC-1 levels. The significance of stromal MIC-1 stores was evaluated in prostate cancer tissue cores, which show major variation in stromal levels of MIC-1. Stromal MIC-1 levels are linked to prostate cancer outcome following radical prostatectomy, with decreasing stromal levels providing an important independent predictor of disease relapse. In low-grade localized prostate cancer (Gleason sum score < or = 6), the level of MIC-1 stromal stores was the best predictor of future relapse when compared with all other clinicopathologic variables. The secretion and ECM association of unprocessed proMIC-1 is likely to play a central role in modulating local bioavailability of MIC-1 which can affect patient outcome in prostate cancer and other epithelial tumors.

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.

c-Myc overexpression and endocrine resistance in breast cancer.

The oncoprotein c-Myc is frequently overexpressed in breast cancer and ectopic expression in breast cancer cell lines attenuates responses to antiestrogen treatment. Here, we review preliminary data aimed at further elucidating a potential role for c-Myc in clinical endocrine resistance in breast cancer. Immunohistochemical and semi-quantitative PCR revealed that c-Myc protein and c-myc mRNA were frequently overexpressed in both ER-positive and ER-negative breast carcinoma. Furthermore, both constitutive and inducible c-Myc overexpression in MCF-7 breast cancer cell lines markedly reduced their sensitivity to the growth inhibitory effects of the pure antiestrogen ICI 182,780. In order to identify potential downstream targets of c-Myc that mediate this effect, Affymetrix microarrays were employed to examine the patterns of gene expression shared by MCF-7 cells stimulated by estrogen, or by induction of c-Myc. Approximately 50% of estrogen target genes identified 6h after treatment were also regulated by c-Myc. One novel target, EMU4, was transcriptionally regulated by c-Myc. In addition, there was a strong correlation between c-myc and EMU4 mRNA expression in a battery of breast cancer cell lines. These data confirm that c-Myc overexpression is a common event in breast cancer, and that this is associated with resistance to antiestrogens in vitro. Furthermore, the development of an experimental paradigm for the discovery of c-Myc and estrogen target genes associated with endocrine resistance provides a framework for the discovery and validation of genes involved in estrogen signalling, and c-Myc-mediated-antiestrogen resistance.

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.

Mutant p53 and cyclin A1 protein expression in primary laryngeal squamous cell carcinomas do not correlate to second primary tumours of the head and neck.

BACKGROUND: Field cancerization is a feature of head and neck squamous cell carcinoma. No biological marker in the index tumour has been correlated to the development of second primary tumours (SPT). Cyclin A1 is a cell cycle regulator and a downstream target of p53. This study assessed predictive correlation of cyclin A1 and mut-p53 with clinicopathological parameters and occurrence of (SPT) in the head and neck. METHODS: Using immunohistochemistry 106 patients treated for primary laryngeal squamous cell carcinoma were investigated for expression of cyclin A1 and mut-p53. RESULTS: Expression of cyclin A1 and mut-p53 were noted in 83 of 106 (78.3%) and 25 of 106 (23.6%) patients. There was a weak but significant correlation between mut-p53 and cyclin A1 (r = 0.301, P = 0.002) expression. During the follow-up period (median 41.0 months (range 1-205 months)), 21 of 106 (19.8%) patients developed an SPT. There was no statistically significant correlation between the markers investigated and disease recurrence, SPT diagnosis or clinicopathological parameters. CONCLUSION: Second primary tumours are an intriguing problem in treatment of HNSCC and a predictive marker identifying those greatest at risk would be a leap forward.

Prediction of local recurrence, distant metastases, and death after breast-conserving therapy in early-stage invasive breast cancer using a five-biomarker panel.

PURPOSE: To determine the clinical utility of intrinsic molecular phenotype after breast-conserving therapy (BCT) with lumpectomy and whole-breast irradiation with or without a cavity boost. PATIENTS AND METHODS: Four hundred ninety-eight patients with invasive breast cancer were enrolled into a randomized trial of BCT with or without a tumor bed radiation boost. Tumors were classified by intrinsic molecular phenotype as luminal A or B, HER-2, basal-like, or unclassified using a five-biomarker panel: estrogen receptor, progesterone receptor, HER-2, CK5/6, and epidermal growth factor receptor. Kaplan-Meier and Cox proportional hazards methodology were used to ascertain relationships to ipsilateral breast tumor recurrence (IBTR), locoregional recurrence (LRR), distant disease-free survival (DDFS), and death from breast cancer. RESULTS: Median follow-up was 84 months. Three hundred ninety-four patients were classified as luminal A, 23 were luminal B, 52 were basal, 13 were HER-2, and 16 were unclassified. There were 24 IBTR (4.8%), 35 LRR (7%), 47 distant metastases (9.4%), and 37 breast cancer deaths (7.4%). The overall 5-year disease-free rates for the whole cohort were: IBTR 97.4%, LRR 95.6%, DDFS 92.9%, and breast cancer-specific death 96.3%. A significant difference was observed for survival between subtypes for LRR (P = .012), DDFS (P = .0035), and breast cancer-specific death (P = .0482), but not for IBTR (P = .346). CONCLUSION: The 5-year and 10-year survival rates varied according to molecular subtype. Although this approach provides additional information to predict time to IBTR, LRR, DDFS, and death from breast cancer, its predictive power is less than that of traditional pathologic indices. This information may be useful in discussing outcomes and planning management with patients after BCT.

Zinc-alpha2-glycoprotein expression as a predictor of metastatic prostate cancer following radical prostatectomy.

The risk of metastatic progression for prostate cancer patients who undergo radical prostatectomy is best estimated presently based on prostate-specific antigen (PSA) doubling time (PSADT). However, additional markers of risk are needed to identify patients who may benefit from aggressive salvage treatment. A decrease in zinc-alpha2-glycoprotein (AZGP1) mRNA levels in malignant prostate epithelium was previously shown to predict biochemical recurrence, as defined by rising levels of serum PSA after radical prostatectomy. We assessed the reliability with which AZPG1 expression could predict clinical recurrence and metastatic progression. Using immunohistochemical methods, we analyzed AZPG1 expression in malignant prostate epithelium in prostatectomy specimens from 228 prostate cancer patients. Low (i.e., absent or weak) AZGP1 expression was associated with clinical recurrence (defined as confirmed localized recurrence, metastasis, or death from prostate cancer; hazard ratio [HR] = 4.8, 95% confidence interval [CI] = 2.2 to 10.7, P<.001) and with bony metastases or death from prostate cancer (HR = 8.0, 95% CI = 2.6 to 24.3, P<.001). Among the 17 patients in the cohort in whom clinical recurrence was associated with short PSADT, absent or weak AZGP1 expression was observed in 13 patients. If these preliminary findings are validated in independent cohorts, the measurement of AZGP1 levels in radical prostatectomy specimens may permit an accurate and timely assessment of risk of metastatic progression after radical prostatectomy.