Poor Prostate Cancer Outcomes Research Articles

Proliferation and tissue remodeling in cancer: the hallmarks revisited

Although cancers are highly heterogeneous at the genomic level, they can manifest common patterns of gene expression. Here, we use gene expression signatures to interrogate two major processes in cancer, proliferation and tissue remodeling. We demonstrate that proliferation and remodeling signatures are partially independent and result in four distinctive cancer subtypes. Cancers with the proliferation signature are characterized by signatures of p53 and PTEN inactivation and concomitant Myc activation. In contrast, remodeling correlates with RAS, HIF-1α and NFκB activation. From the metabolic point of view, proliferation is associated with upregulation of glycolysis and serine/glycine metabolism, whereas remodeling is characterized by a downregulation of oxidative phosphorylation. Notably, the proliferation signature correlates with poor outcome in lung, prostate, breast and brain cancer, whereas remodeling increases mortality rates in colorectal and ovarian cancer.

Abstract 2615: Genetic variations in angiogenesis-related genes in prostate cancer recurrence

Abstract Introduction: Prostate cancer is the most common cancer and the second leading cause of cancer death in American men. Among patients who have a radical prostatectomy, ∼30% will have disease recurrence. Currently, the level of prostate specific antigen (PSA), clinical stage (TNM) and tumor grade (Gleason score) are used to estimate prognosis and inform treatment modalities. Although these are extremely useful, additional biomarkers are needed to better predict outcome. Angiogenesis has been associated with Gleason score, tumor stage, progression, metastasis and survival in prostate cancer. We hypothesized that single nucleotide polymorphisms (SNPs) in genes in the angiogenesis pathway may be associated with prostate cancer recurrence. Methods: In a historical cohort of 1061 prostatectomy cases treated at the Moffitt Cancer Center from 1986 to 2003, we identified 311 recurrent cases and 750 non-recurrent cases. A recurrent case was defined by either an elevated PSA level after surgical treatment, clinical metastasis or disease specific death. All other patients were categorized as non-recurrent. We compared genotype frequencies of 2,981 SNPs in 547 angiogenesis genes between the two groups. Genotyping was performed using the Illumina GoldenGate assay and associations between recurrence-free survival and individual SNPs were evaluated using competing Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) under three inheritance models (dominant, recessive and log-additive model). For each SNP, the minimum P-value among all tested inheritance models was selected. We calculated q-values to estimate false discovery rates. Results: The mean age at diagnosis of the study subjects was 59.7 (SD=7.5) years. The recurrence rate was 29.3% with a median recurrence-free survival of 200.8 (range=179.0-241.9) months. A total of 91 SNPs in 56 angiogenesis genes had raw P-values less than 0.01 and q-values less than 3%. We found associations for several families of genes that have been previously associated with aggressiveness and/or survival of prostate cancer, such as cadherins (CDH,11 SNPs), fibroblast growth factor and its receptor (FGF/FGFR, 6 SNPs), insulin-like growth factor and its receptor (IGF/IGFR, 3 SNPs), interleukins (IL, 5 SNPs), metalloproteinases (MMP, 3 SNPs) and thrombospondin (THBS, 4 SNPs). The most significant association was observed for rs889730 in CDH13 (HR= 0.69, 95%CI=0.58-0.83, P=0.000057, additive model). CDH13 contributes to promotion of tumor neovascularization, but down regulation has been associated with a poor outcome in prostate cancer. Conclusion: Data from this comprehensive study of angiogenesis genes and prostate cancer suggests that variants in angiogenesis-related genes may influence prostate cancer recurrence after radical prostatectomy. Further studies are warranted to confirm these preliminary findings. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2615. doi:1538-7445.AM2012-2615

Abstract 116: Targeting hypoxia for the identification of novel biomarkers for prostate cancer

Abstract Tumor-associated hypoxia has been associated with malignant progression, metastasis, resistance to therapy, and poor clinical outcome in prostate cancer (CaP). Prompted by the evidence that hypoxia affects CaP, we studied global gene expression in 100 CaP tissues and 71 samples of adjacent benign tissues. RNA was extracted from cancer cells isolated by laser-capture microdissection (LCM) or without isolation (“bulk tissue”). We found 24 hypoxia-associated genes significantly overexpressed in CaP (p≤0.02), both in bulk tissue and LCM. Among hypoxia-associated genes, the disc large (drosophila) homolog-associated protein 5 (DLG7), hyaluronan-mediated motility receptor (HMMR) and cyclin B1 (CCNB1) were associated with Gleason score and systemic progression. Since the products of HMMR and CCNB1 have been recently identified as molecular markers of CaP progression, we postulated that DLG7 has prognostic value also. To test this hypothesis we measured transcript levels for DLG7 in a 150-pair case-control cohort. The cases (progression to systemic disease within five years of surgery) and controls (no progression within seven years) were matched for clinical and pathologic prognostic variables, including grade, stage, and preoperative serum levels of PSA. The overall prognostic ability of DLG7, as tested in receiver operating characteristic analysis was of 0.74 (95% CL, 0.68 to 0.8), independent of the for ERG status. Overall, our data indicate that DLG7, a hypoxia-controlled gene have a prognostic value in high-risk CaP. To better define the value of DLG7 as a molecular predictor of CaP progression, we are currently assessing DLG7 protein levels by immunohistochemistry. Then we will analyze the association of DLG7 levels with clinical parameters. Introduction of oxygen tension as a variable may constitute a tool for the identification of novel biomarkers for CaP. Present address CRG: University of Mississippi Cancer Institute, Jackson, MS, USA. Support: DOD PC094680 (CRG), PCF Creativity Award (CRG), Mayo Clinic Prostate SPORE 5P50CA091956 (SV-P); Mrs. Adelyn L. Luther, Singer Island, Florida and Mayo Clinic Cancer Center (SV-P). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 116. doi:1538-7445.AM2012-116

Highlights of This Issue

Next generation sequencing and array CGH analysis of one patient's neuroendocrine prostate cancer revealed a homozygous deletion of the methylthioadenine phosphorylase (MTAP) gene. Concurrently, a patient-derived xenograft model was established. A novel two-drug therapy markedly decreased xenograft growth rate and increased cancer cell apoptosis, without toxicity to the mouse host. Moreover, decreased MTAP expression was strongly associated with poor outcome in prostate cancer. This study suggests a unique therapy for patients with MTAP- deficient cancers, with significant implications for personalized oncology, since MTAP is absent in 10 to 75 % of the most intractable kinds of human cancers.Non-small cell lung cancer (NSCLC) remains one of the most difficult to treat malignancies, and novel therapeutics and patient selection strategies are urgently needed. The uracil-metabolizing enzyme dUTPase is reported to protect tumor cells from aberrant uracil misincorporation into DNA during treatment with thymidylate synthase (TS)-targeted therapies. Wilson and colleagues report that dUTPase is significantly overexpressed in NSCLC cell lines and clinical specimens and show that the silencing of dUTPase expression dramatically sensitizes NSCLC cells to cytotoxicity induced by the TS inhibitors pemetrexed and fluorodeoxyuridine. Targeting dUTPase represents a novel mechanism-based therapeutic approach to significantly enhance the efficacy of TS-targeted chemotherapies.Antibodies that block ligand binding to the type-1 insulin-like growth factor receptor (IGF-1R) have limited clinical antitumor activity. Bid and colleagues examined the effect of the SCH717454 antibody on angiogenesis in vitro and in vivo. Antibody blockade of IGF-1R prevented VEGF-stimulated proliferation of vascular endothelial cells, providing the first direct evidence of the involvement of IGF-1R signaling in angiogenesis. Both in vitro and in a mouse model, IGF-2 circumvented the inhibitory activity of SCH717454. The data yield insight into the mechanism of action and resistance to receptor-targeted antibodies and for improved strategies for targeting the IGF-axis for cancer treatment.To achieve the full potential of single-agent therapies targeting specific signaling proteins, it is essential to explore why drug resistance occurs in the majority of treated patients over time. Chen and colleagues investigated the role of alternative signaling pathways in mediating resistance to lapatinib inhibition of HER2-amplified gastric cancer cells. The data showed that activation of MET receptor in MET-overexpressing cells can overcome HER2 inhibition by restoring common downstream signaling pathways more effectively than the activation of other receptor tyrosine kinases. Thus, this finding suggests MET activation as a potential mechanism of resistance to lapatinib inhibition.

Molecular classification of prostate cancer using curated expression signatures

High Gleason score is currently the best prognostic indicator for poor prognosis in prostate cancer. However, a significant number of patients with low Gleason scores develop aggressive disease as well. In an effort to understand molecular signatures associated with poor outcome in prostate cancer, we analyzed a microarray dataset characterizing 281 prostate cancers from a Swedish watchful-waiting cohort. Patients were classified on the basis of their mRNA microarray signature profiles indicating embryonic stem cell expression patterns (stemness), inactivation of the tumor suppressors p53 and PTEN, activation of several oncogenic pathways, and the TMPRSS2-ERG fusion. Unsupervised clustering identified a subset of tumors manifesting stem-like signatures together with p53 and PTEN inactivation, which had very poor survival outcome, a second group with intermediate survival outcome, characterized by the TMPRSS2-ERG fusion, and three groups with benign outcome. The stratification was validated on a second independent dataset of 150 tumor and metastatic samples from a clinical cohort at Memorial Sloan-Kettering Cancer Center. This classification is independent of Gleason score and therefore provides useful unique molecular profiles for prostate cancer prognosis, helping to predict poor outcome in patients with low or average Gleason scores.

Obesity is associated with castration‐resistant disease and metastasis in men treated with androgen deprivation therapy after radical prostatectomy: results from the SEARCH database

Study Type - Prognosis (cohort series). Level of Evidence 2a. What's known on the subject? and What does the study add? The incidence and prevalence of obesity in the USA and Europe is increasing. Higher body mass index is associated with a lower risk of overall prostate cancer diagnosis but also with an increased risk of high grade prostate cancer. Obese men undergoing primary therapy with radical prostatectomy or external beam radiation are more likely to experience a biochemical recurrence after treatment compared with normal weight men. Finally, obesity is associated with increased prostate-cancer-specific mortality. We hypothesized that obese men on androgen deprivation therapy may be at increased risk for prostate cancer progression. Previous studies have shown that obese men have lower levels of testosterone compared with normal weight men. Additionally, one previous study found that obese men have higher levels of testosterone on androgen deprivation therapy. Men with higher levels of testosterone on androgen deprivation therapy are at increased risk of prostate cancer progression. We found that men with higher body mass index were at increased risk of progression to castration-resistant prostate cancer, development of metastases and prostate-cancer-specific mortality. When we adjusted for various clinicopathological characteristics, obese men were at increased risk of progression to castration-resistant prostate cancer and development of metastases. The results of our study help generate hypotheses for further study regarding the mechanisms between obesity and aggressive prostate cancer. • To investigate whether obesity predicts poor outcomes in men starting androgen deprivation therapy (ADT) before metastasis, since previous studies found worse outcomes after surgery and radiation for obese men. • A retrospective review was carried out of 287 men in the SEARCH database treated with radical prostatectomy between 1988 and 2009. • Body mass index (BMI) was categorized to <25, 25-29.9 and ≥ 30 kg/m2. • Proportional hazards models were used to test the association between BMI and time to castration-resistant prostate cancer (PC), metastases and PC-specific mortality adjusting for demographic and clinicopathological data. • During a median 73-month follow-up after radical prostatectomy, 403 men (14%) received early ADT. • Among 287 men with complete data, median BMI was 28.3 kg/m2. • Median follow-up from the start of ADT was 52 months during which 44 men developed castration-resistant PC, 34 developed metastases and 24 died from PC. • In multivariate analysis, higher BMI was associated with a trend for greater risk of progression to castration-resistant PC (P= 0.063), a more than threefold increased risk of developing metastases (P= 0.027) and a trend toward worse PC-specific mortality (P= 0.119). • Prognostic biomarkers did not differ between BMI groups. • Among men treated with early ADT, our results suggest that obese men may have increased risk of PC progression. • These data support the general hypothesis that obesity is associated with aggressive PC, although validation of these findings and further study of the mechanisms linking obesity and poor PC outcomes are required.

Knockdown of MTDH Sensitizes Endometrial Cancer Cells to Cell Death Induction by Death Receptor Ligand TRAIL and HDAC Inhibitor LBH589 Co-Treatment

Understanding the molecular underpinnings of chemoresistance is vital to design therapies to restore chemosensitivity. In particular, metadherin (MTDH) has been demonstrated to have a critical role in chemoresistance. Over-expression of MTDH correlates with poor clinical outcome in breast cancer, neuroblastoma, hepatocellular carcinoma and prostate cancer. MTDH is also highly expressed in advanced endometrial cancers, a disease for which new therapies are urgently needed. In this present study, we focused on the therapeutic benefit of MTDH depletion in endometrial cancer cells to restore sensitivity to cell death. Cells were treated with a combination of tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL), which promotes death of malignant cells of the human reproductive tract, and histone deacetylase (HDAC) inhibitors, which have been shown to increase the sensitivity of cancer cells to TRAIL-induced apoptosis. Our data indicate that depletion of MTDH in endometrial cancer cells resulted in sensitization of cells that were previously resistant in response to combinatorial treatment with TRAIL and the HDAC inhibitor LBH589. MTDH knockdown reduced the proportion of cells in S and increased cell arrest in G2/M in cells treated with LBH589 alone or LBH589 in combination with TRAIL, suggesting that MTDH functions at the cell cycle checkpoint to accomplish resistance. Using microarray technology, we identified 57 downstream target genes of MTDH, including calbindin 1 and galectin-1, which may contribute to MTDH-mediated therapeutic resistance. On the other hand, in MTDH depleted cells, inhibition of PDK1 and AKT phosphorylation along with increased Bim expression and XIAP degradation correlated with enhanced sensitivity to cell death in response to TRAIL and LBH589. These findings indicate that targeting or depleting MTDH is a potentially novel avenue for reversing therapeutic resistance in patients with endometrial cancer.

Abstract 2597: PLA2G7 associates with aggressive prostate cancer in vivo and regulates prostate cancer cell migration and adhesion in vitro

Abstract There is an urgent need for more efficient and more targeted methods of prostate cancer treatment. We have previously shown PLA2G7 (also known as lipoprotein-associated phospholipase A2, Lp-PLA2) to be a possible biomarker and drug target especially in ERG positive prostate cancers by combining gene expression data from prostate cancer tissues in vivo and functional RNAi studies in vitro. To further study the potential of PLA2G7 in prostate cancer management immunohistochemical staining of 119 clinical prostate cancer samples and 112 adjacent normal prostate samples were performed. In addition, a global lipidomic, eicosanoid and gene expression analysis was utilized to study the effect of PLA2G7 silencing in ERG oncogene positive prostate cancer cells. The results emphasized high expression of PLA2G7 in 66 % of the cancer samples, whereas less than 4 % of the adjacent normal tissues showed positive staining. Furthermore, PLA2G7 expression significantly correlated with high Gleason score. PLA2G7 silencing in vitro induced a reduction in the amount of lysophosphatidyl choline and leukotriene E4, as well as in the expression of multiple genes and signaling pathways involved in cell adhesion and motility. In accordance, knock-down of PLA2G7 in 3D prostate cancer cell culture model lead to decreased invasion to extracellular matrix. Interestingly, PLA2G7 silencing also reduced the expression of ALDH1A1, a marker for malignant prostate stem cells and predictor of poor prostate cancer outcome. In conclusion, these novel findings suggest an oncogenic role for PLA2G7 in aggressive prostate cancers and support the rationale for PLA2G7 targeted therapy in these cancers. A novel PLA2G7 inhibitor is currently under clinical evaluation for cardiovascular diseases, presenting thus an interesting opportunity for drug repositioning to other indications, such as prostate cancer. In addition, lipid-lowering statins are known to lower PLA2G7 mass and activity, therefore PLA2G7 may also represent a target of lipid-lowering therapy in reducing the risk of aggressive prostate cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2597. doi:10.1158/1538-7445.AM2011-2597

Subcellular localization of p27 and prostate cancer recurrence: automated digital microscopy analysis of tissue microarrays

Previous investigations have linked decreased nuclear expression of the cell cycle inhibitor p27 with poor outcome in prostate cancer. However, these reports are inconsistent regarding the magnitude of that association and its independence from other predictors. Moreover, cytoplasmic translocation of p27 has been proposed as a negative prognostic sign. Given the cost and accuracy limitations of manual scoring, particularly of tissue microarrays, we determined if laser-based fluorescence microscopy could provide automated analysis of p27 in both nuclear and cytoplasmic locations and, thus, clarify its significance as a prognostic biomarker. We constructed tissue microarrays covering 202 recurrent cases (rising prostate-specific antigen) and 202 matched controls without recurrence. Quadruplicate tumor samples encompassed 5 slides and 1616 cancer histospots. Cases and controls matched on age, Gleason grade, stage, and hospital. We immunolabeled epithelial cytoplasm with Alexafluor 647, p27 with Alexafluor 488, and nuclei with 4c6-diamidino-2-phenylindole·2HCl. Slides were scanned on an iCys laser scanning cytometer (CompuCyte Corp, Cambridge, MA). Nuclear crowding required a stereological approach--random arrays of circles (phantoms) were layered on images and the content of each phantom was analyzed in scatter plots. Both nuclear and cytoplasmic p27 were significantly lower in cases versus controls (P = .014 and P = .004, respectively). Regression models controlling for matching variables plus prostate-specific antigen showed strong linear trends for increased risk of recurrence with lower p27 in both nucleus and cytoplasm (highest versus lowest quartile; odds ratio, 0.35; P = .006). Manual scoring identified an inverse association between p27 expression and tumor grade but no independent association with recurrence. In conclusion, we developed an automated method for subcellular scoring of p27 without the need to segment individual cells. Our method identified a strong relationship, independent of tumor grade, stage, and prostate-specific antigen, between p27 expression--regardless of subcellular location--and prostate cancer recurrence. This relationship was not observed with manual scoring.

Context-Dependent Effects of Genome-Wide Association Study Genotypes and Macroenvironment on Time to Biochemical (Prostate Specific Antigen) Failure after Prostatectomy

Disparities in cancer defined by race, age, or gender are well established. However, demographic metrics are surrogates for the complex contributions of genotypes, exposures, health care, socioeconomic and sociocultural environment, and many other factors. Macroenvironmental factors represent novel surrogates for exposures, lifestyle, and other factors that are difficult to measure but might influence cancer outcomes. We applied a "multilevel molecular epidemiology" approach using a prospective cohort of 444 White prostate cancer cases who underwent prostatectomy and were followed until biochemical failure (BF) or censoring without BF. We applied Cox regression models to test for joint effects of 86 genome-wide association study-identified genotypes and macroenvironment contextual effects after geocoding all cases to their residential census tracts. All analyses were adjusted for age at diagnosis and tumor aggressiveness. Residents living in census tracts with a high proportion of older single heads of household, high rates of vacant housing, or high unemployment had shorter time until BF postsurgery after adjustment for patient age and tumor aggressiveness. After correction for multiple testing, genotypes alone did not predict time to BF, but interactions predicting time to BF were observed for MSMB (rs10993994) and percentage of older single heads of households (P = 0.0004), and for HNF1B/TCF2 (rs4430796) and census tract per capita income (P = 0.0002). The context-specific macroenvironmental effects of genotype might improve the ability to identify groups that might experience poor prostate cancer outcomes. Risk estimation and clinical translation of genotype information might require an understanding of both individual- and macroenvironment-level context.

Fatty acid synthase polymorphisms, tumor expression, body mass index, prostate cancer risk, and survival.

Fatty acid synthase (FASN) regulates de novo lipogenesis, body weight, and tumor growth. We examined whether common germline single nucleotide polymorphisms (SNPs) in the FASN gene affect prostate cancer (PCa) risk or PCa-specific mortality and whether these effects vary by body mass index (BMI). In a prospective nested case-control study of 1,331 white patients with PCa and 1,267 age-matched controls, we examined associations of five common SNPs within FASN (and 5 kb upstream/downstream, R(2) > 0.8) with PCa incidence and, among patients, PCa-specific death and tested for an interaction with BMI. Survival analyses were repeated for tumor FASN expression (n = 909). Four of the five SNPs were associated with lethal PCa. SNP rs1127678 was significantly related to higher BMI and interacted with BMI for both PCa risk (P(interaction) = .004) and PCa mortality (P(interaction) = .056). Among overweight men (BMI > or = 25 kg/m(2)), but not leaner men, the homozygous variant allele carried a relative risk of advanced PCa of 2.49 (95% CI, 1.00 to 6.23) compared with lean men with the wild type. Overweight patients carrying the variant allele had a 2.04 (95% CI, 1.31 to 3.17) times higher risk of PCa mortality. Similarly, overweight patients with elevated tumor FASN expression had a 2.73 (95% CI, 1.05 to 7.08) times higher risk of lethal PCa (P(interaction) = .02). FASN germline polymorphisms were significantly associated with risk of lethal PCa. Significant interactions of BMI with FASN polymorphisms and FASN tumor expression suggest FASN as a potential link between obesity and poor PCa outcome and raise the possibility that FASN inhibition could reduce PCa-specific mortality, particularly in overweight men.

A 25-Year Prospective Study of Plasma Adiponectin and Leptin Concentrations and Prostate Cancer Risk and Survival

Adipocytokines may mediate the association between adiposity and lethal prostate cancer outcomes. In the Physicians' Health Study, we prospectively examined the association of prediagnostic plasma concentrations of adiponectin and leptin with risk of developing incident prostate cancer (654 cases diagnosed 1982-2000 and 644 age-matched controls) and, among cases, risk of dying from prostate cancer by 2007. Adiponectin concentrations were not associated with risk of overall prostate cancer. However, men with higher adiponectin concentrations had lower risk of developing high-grade or lethal cancer (metastatic or fatal disease). The relative risk (95% CI) comparing the highest quintile to the lowest (Q5 vs Q1) was 0.25 (95% CI 0.07-0.87; P(trend) = 0.02) for lethal cancer. Among all the cases, higher adiponectin concentrations predicted lower prostate cancer-specific mortality [hazard ratio (HR)(Q5 vs Q1)= 0.39; 95% CI 0.17-0.85; P(trend) = 0.02], independent of body mass index (BMI), plasma C-peptide (a marker of insulin secretion), leptin, clinical stage, and tumor grade. This inverse association was apparent mainly among men with a BMI >or=25 kg/m(2) (HR(Q5 vs Q1)= 0.10; 95% CI 0.01-0.78; P(trend) = 0.02), but not among men of normal weight (P(trend) = 0.51). Although the correlation of leptin concentrations with BMI (r = 0.58, P < 0.001) was stronger than that of adiponectin (r = -0.17, P < 0.001), leptin was unrelated to prostate cancer risk or mortality. Higher prediagnostic adiponectin (but not leptin) concentrations predispose men to a lower risk of developing high-grade prostate cancer and a lower risk of subsequently dying from the cancer, suggesting a mechanistic link between obesity and poor prostate cancer outcome.

MUC1 Expression in Incidental Prostate Cancer Predicts Staging and Grading on the Subsequent Radical Prostatectomy

The behavior of Incidental prostate cancer (IPC) cannot be reliably predicted by means of conventional histomorphology. MUC1 (episialin) expression has been linked to poor outcome in peripheral prostate cancer (PC). We aimed to determine the so far neglected prognostic role of MUC1 expression in IPC which most commonly represents transition zone cancer. Using Tissue microarray (TMA), we assessed the association between MUC1 expression recorded in transurethral resection specimens of the prostate (TURP chips) and histopathologic outcome parameters (Gleason scores and histologic staging) performed on the subsequent radical prostatectomies (RPs) in a study cohort of 54 patients. Due to tissue loss during arraying and sectioning, a total of 44 (81.5%) tumor samples remained available for immunostaining which was dichotomized by two independent clinical pathologists as being absent or present. MUC1 expression was present in 7 (15.9%) of the 44 IPC immunohistochemically investigated with a striking over-representation in high stage tumors, and was significantly correlated with histopathologic staging (ρ = 0.4; p = 0.02) and Gleason scores (ρ = 0.3; p = 0.03) performed on the corresponding RPs. These data were confirmed by means of the McNemar test (staging: p = 0.01; grading: p = 0.04). Our findings suggest that MUC1 might become a valuable adjunct to enable individual prognostic ramification prior to radical surgery in prostate cancer histologically detected in TURP chips. This interesting observation clearly awaits validation by larger studies surveying clinical follow-up data.

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.

TEAD1 and c-Cbl are novel prostate basal cell markers that correlate with poor clinical outcome in prostate cancer.

Prostate cancer is the most frequently diagnosed male cancer, and its clinical outcome is difficult to predict. The disease may involve the inappropriate expression of genes that normally control the proliferation of epithelial cells in the basal layer and their differentiation into luminal cells. Our aim was to identify novel basal cell markers and assess their prognostic and functional significance in prostate cancer. RNA from basal and luminal cells isolated from benign tissue by immunoguided laser-capture microdissection was subjected to expression profiling. We identified 112 and 267 genes defining basal and luminal populations, respectively. The transcription factor TEAD1 and the ubiquitin ligase c-Cbl were identified as novel basal cell markers. Knockdown of either marker using siRNA in prostate cell lines led to decreased cell growth in PC3 and disrupted acinar formation in a 3D culture system of RWPE1. Analyses of prostate cancer tissue microarray staining established that increased protein levels of either marker were associated with decreased patient survival independent of other clinicopathological metrics. These data are consistent with basal features impacting on the development and clinical course of prostate cancers.

THE IMPACT OF OBESITY ON BIOCHEMICAL FAILURE AFTER RADICAL PROSTATECTOMY IN AFRICAN-AMERICAN AND EUROPEAN AMERICAN PATIENTS

428 THE IMPACT OF OBESITY ON BIOCHEMICAL FAILURE AFTER RADICAL PROSTATECTOMY IN AFRICAN-AMERICAN AND EUROPEAN AMERICAN PATIENTS Benjamin M Brucker*, Meredith Bergey, Matthew J Resnick, Seema Sonnad, Daniel Canter, Thomas J Guzzo, Timothy R Rebbeck, Alan J Wein, S Bruce Malkowicz. Philadelphia, PA, and Baltimore, MD. INTRODUCTION AND OBJECTIVE: The relationship between body mass index (BMI) and prostate cancer deserves investigation as the obesity epidemic is nearing a health care crisis. Racial differences have been implicated in explaining poorer prostate cancer outcomes among African-Americans. We evaluated the role of race and obesity on PSA-free survival in a cohort of men larger than we had previously reported. This was drawn from a radical prostatectomy database from 1991 to 2005. METHODS: There were a total of 2,163 patients from a prospectively maintained database of radical prostatectomy patients were evaluated for the impact of obesity on pathologic and clinical

Duplicated TMPRSS2–ERG fusion predicts extremely poor outcome in prostate cancer

Duplicated TMPRSS2–ERG fusion predicts extremely poor outcome in prostate cancer

Hypoxia down-regulates DNA double strand break repair gene expression in prostate cancer cells

Background and purpose Intratumoral hypoxia has been correlated with poor clinical outcome in prostate cancer. Prostate cancer cells can be genetically unstable and have altered DNA repair. We, therefore, hypothesized that the expression of DNA double-strand break (DNA-dsb) repair genes in normal and malignant prostate cultures can be altered under hypoxic conditions. Methods and materials The expression of homologous recombination (HR) and non-homologous recombination (NHEJ) genes following gas hypoxia (0.2%) or exposure to HIF1α-inducing agent, CoCl 2 (100 μM), was determined for normal diploid fibroblasts (GM05757) and the pre-malignant and malignant prostate cell lines, BPH-1, 22RV-1, DU145 and PC3. RNA and protein levels were determined using RT-PCR and Western blotting. Additionally, p53 genotype and function, the level of hypoxia-induced apoptosis, and cell cycle distribution, were determined to correlate to changes in DNA-dsb gene expression. Results Induction of hypoxia was confirmed using HIF1α and VEGF expression in gas- and CoCl 2-treated cultures. Hypoxia (48–72 h of 0.2% O 2) decreased RNA expression of a number of HR-related genes (e.g. Rad51, Rad52, Rad54, BRCA1, BRCA2) in both normal and malignant cultures. Similar decreases in RNA pertaining to the NHEJ-related genes (e.g. Ku70, DNA-PKcs, DNA Ligase IV, Xrcc4) were observed. In selected cases, hypoxia-mediated decreases in RNA expression led to decreased DNA-dsb protein expression. CoCl 2-treated cultures did not show decreased DNA-dsb protein expression. The ability of hypoxia to down-regulate Rad51 and other HR-associated genes under hypoxia was not correlated to c-Abl or c-Myc gene expression, p53 genotype or function, propensity for hypoxia-mediated apoptosis, or specific changes in cell cycle distribution. Conclusions Hypoxia can down-regulate expression of DNA-dsb repair genes in both normal and cancer cells. If associated with a functional decrease in DNA-dsb repair, this observation could provide a potential basis for the observed genetic instability within tumor cells exposed to hypoxia.

TESTOSTERONE AS A PREDICTOR OF PATHOLOGICAL STAGE IN CLINICALLY LOCALIZED PROSTATE CANCER

Substantial controversy exists in the literature regarding the association between pretreatment testosterone and disease outcome in patients with prostate cancer. We explored the relationship between preoperative total testosterone, and pathological stage and progression in patients with clinically localized prostate cancer treated with radical prostatectomy. We retrospectively reviewed the records of consecutive patients with clinically localized prostate cancer treated with radical prostatectomy between January 1990 and June 2003. A total of 326 patients with pretreatment testosterone levels available were eligible for this analysis. Biochemical progression (BCR) was defined by postoperative prostate specific antigen (PSA) greater than 0.4 ng/ml with a confirmatory increase and it occurred in 41 men. No men received adjuvant therapy. Univariate and multivariate logistic regression analyses were done to examine whether pretreatment testosterone was associated with pathological stage. Cox regression was used to assess the association of testosterone and BCR. Median PSA was 6.01 ng/ml (range 0.13 to 86), testosterone was 385 ng/dl (range 133 to 998) and followup was 36 months (range 4 to 136). In 245 patients (75%) disease was organ confined. Lower testosterone correlated with adverse pathological stage on multivariate analysis (p = 0.01), as did clinical stage, biopsy grade and PSA. However, we found no relationship between testosterone and BCR after adjusting for covariates. Furthermore, we found no evidence of an interaction between PSA and testosterone (p = 0.4). On multivariate analysis low preoperative total testosterone was associated with advanced pathological stage but not with BCR. Future studies are warranted with data on more patients who have progressed.

Signal transduction pathways in androgen-dependent and -independent prostate cancer cell proliferation

In a previous report, we showed that increased activation of Akt, a downstream effector of phosphoinositide 3-kinase (PI3K) together with decreased activation of extracellular-signal-regulated kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family, predicted poor clinical outcome in prostate cancer (Kreisberg et al. 2004 Cancer Research 64 5232-5236). We now show that Akt activation, but not ERK activation, is correlated with proliferation in human prostate tumors as estimated by the expression of the cell proliferation antigen Ki67. We verified these results in vitro, using the androgen-dependent prostate cancer cell line LNCaP and its androgen-independent clone C4-2 as models of prostate cancer of good and poor clinical outcome, respectively. C4-2 cells expressed higher Akt activation, lower ERK activation and increased proliferation compared with LNCaP cells, similar to cases of poor clinical outcome. The PI3K inhibitor LY294002, but not the MAPK/ERK kinase inhibitor PD98059, induced growth arrest in both cell lines. Transient transfection with constitutively active Akt increased proliferation while dominant negative Akt decreased it, thus showing that Akt plays an important role in prostate cancer proliferation. Akt regulates the expression and activation of the androgen receptor. Androgen receptor inhibition with Casodex induced growth arrest in LNCaP cells, but not in C4-2 cells. Another PI3K downstream effector, p70 S6 kinase, requires prior phosphorylation by mammalian target of rapamycin (mTOR) for complete activation. Activation of p70 S6 kinase was higher in C4-2 compared with LNCaP cells. Rapamycin, an mTOR inhibitor, had a growth-inhibitory effect in C4-2 cells, but not in LNCaP cells. Our data suggest a shift from a Casodex-sensitive proliferation pathway in LNCaP cells to a rapamycin-sensitive pathway in C4-2 cells.