788 FINNISH FAMILIES WITH CLINICALLY AGGRESSIVE PROSTATE CANCER HAVE AN INCREASED RISK TO OTHER CANCERS

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SLC45A3 is a common ETS family fusion partner in prostate cancer

Identification of ETS gene fusions using Affymetrix exon 1.0 arrays

Perner S.1, Pflueger D.1, Rickman D.S.1, Lafargue C.J.1, Svensson M.A.1, Demichelis F.1, Stephan C.2, Dietel M.3, Fritzsche F.R.4, Han B.5, Palanisamy N.5, Mehra R.5, Allory Y.6, Maille P.6, De La Taille A.7, Kuefer R.8, Tewari A.K.9, Chinnaiyan A.M.5, Kristiansen G.4, Rubin M.A.1

Smit F.P., Salagierski M., Hessels D., Jannink S.A., Schalken J.A.

Weill Cornell Medical Center, Dept. of Pathology and Laboratory Medicine, New York, United States of America, 2Charité University Hospital of Berlin, Dept. of Urology, Berlin, Germany, 3 Charité University Hospital of Berlin, Dept. of Pathology, Berlin, Germany, 4University Hospital of Zurich, Dept. of Pathology, Zurich, Switzerland, 5University of Michigan, Dept. of Pathology, Ann Arbor, United States of America, 6CHU Mondor, Dept. of Pathology, Creteil, France, 7 CHU Mondor, Dept. of Urology, Creteil, France, 8University Hospital of Ulm, Dept. of Urology, Ulm, Germany, 9Weill Cornell Medical Center, Dept. of Urology, New York, United States of America

Radboud University Nijmegen Medical Centre, Dept. of Urology, Nijmegen, The Netherlands

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Introduction & Objectives: Recurrent gene fusions between TMPRSS2 and the ETS family transcription factors, most commonly ERG, have been identified in the majority of prostate cancers (PCa). The objective of this study was to characterize a novel gene fusion involving ERG. Material & Methods: ERG and SLC45A3 gene rearrangements were assessed on 634 PCa samples using fluorescence in-situ hybridization (FISH). Gene fusion transcripts and ERG mRNA levels were characterized in 101 PCa samples using conventional and quantitative real-time reverse transcription-PCR. Results: At the genomic and transcript level, we identified a novel gene fusion between the promoter of SLC45A3 and ERG. This fusion yielded ERG mRNA over-expression with levels comparable to those observed in samples harboring the TMPRSS2-ERG fusion. 553 samples could be assessed for ERG and SLC45A3 rearrangement. 37 samples (7%) showed ERG and SLC45A3 rearrangement, most likely resulting in a SLC45A3-ERG fusion, 17 samples (3%) showed SLC45A3 rearrangement only, and 267 samples (48%) showed ERG rearrangement only. Consistent with other studies, we found 55% samples with ERG rearrangement. To date, this is the largest PCa cohort assessed for ERG rearrangement. We found high levels of ERG mRNA overexpression in 90% (26/29) samples that demonstrated ERG rearrangement. We detected 7 TMPRSS2-ERG isoforms but did not observe a relationship between isoform expression and level of ERG over-expression.

Introduction & Objectives: In gene expression analyses, outliers are overor under expressed in only a subset of unhealthy individuals. Cancer Outlier Profile Analysis (COPA) led to the identification of so called gene fusions in prostate cancer (PCa). Our recent study aims to use COPA analysis on the new Affymetrix exon 1.0 arrays to assess the prevalence of outliers in different groups of PCa patients. Material & Methods: Based on the pathology findings of 70 radical prostatectomy specimens four groups of patients were identified: 1) Gleason score < 7 (n=20); 2) Gleason score > 7 (n=22); 3) castration-resistant PCa (n=21); 4) metastatic PCa (n=7). RNA was isolated from each of PCa tissue specimen. Following RNA isolation gene profiling was performed using a microarray technique (GeneChip, Affymetrix). We did a bioinformatic analysis, including COPA on the standard gene set (23,000 genes) and results were validated in RT-PCR for selected genes. Results: 250 outliers genes were identified on a microarray analysis. Potentially relevant genes, including some of the ETS transcription factor family: ETV1, ETV4 and ETV5, were selected for further experiments. The RT-PCR results of selected genes reflected those from microarray analysis. ETV1, ETV4 and ETV5 were over expressed in 4 (5.7 %), 2 (2.8 %) and 2 (2.8 %) of tumours, respectively. The over expression of ETV1 and ETV5 was observed in all cases in a highly aggressive PCa (castration resistant PCa or Gleason score > 7). Conversely, ETV4 was over expressed only in low Gleason score patients.

Conclusions: Based on the characterization of 634 prostate cancer samples, we found that SLC45A3, a prostate-specific, androgen-regulated gene, represents the second most common 5’ fusion partner of ETS genes in prostate cancer. Given the association between ERG gene rearrangement and prostate cancer progression, we hypothesize that tumors harboring the SLC45A3-ERG fusion may demonstrate the same clinical course.

Conclusions: We confirmed in this COPA analysis of expression data from 70 prostate cancers the frequent over expression of ETS oncogenes. Moreover, we were able to show that ETV1 and ETV5 were over expressed in aggressive PCa.





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Association of genetic polymorphisms at 8q24 with the risk of prostate cancer in a Japanese population

Finnish families with clinically aggressive prostate cancer have an increased risk to other cancers

Terada N.1, Tsuchiya N.2, Ma Z.2, Shimizu Y.1, Kobayashi T.1, Nakamura E.1, Kamoto T.1, Habuchi T.2, Ogawa O.1

Pakkanen S.1, Pukkala E.2, Kainulainen H.3, Matikainen M.P.4, Koivisto P.A.5, Schleutker J.6, Tammela T.L.J.4, Prostate Cancer Investigation Study Group

Kyoto University, Dept. of Urology, Kyoto, Japan, 2Akita University, Dept. of Urology, Akita, Japan

Institute of Medical Technology, Laboratory of Cancer Genetics, Tampereen Yliopisto, Finland, 2Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland, 3University of Tampere, Tampere School of Public Health, Tampere, Finland, 4Tampere University Hospital and Medical School, Dept. of Urology, Tampere, Finland, 5Tampere University Hospital, Laboratory of Molecular Genetics, Tampere, Finland, 6Institute of Medical Technology, Cancer Genetics, Tampere, Finland

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Introduction & Objectives: Genetic factors, as well as a combination of environmental factors, contribute to the risk of prostate cancer (PC). Recently, genome-wide linkage studies found several independent single nucleotide polymorphisms (SNPs) that are strongly associated with PC on chromosome 8q24. We analyzed two of these SNPs, rs1447295 and rs6983267, to examine association with the risk of PC in Japanese men. Material & Methods: Between 1993 to 2005, a total of 1018 subjects, consisting of 507 PC patients, 511 non-PC patients, composed of 124 benign prostatic hyperplasia (BPH) patients and 387 normal male controls, were enrolled in this study. SNPs were examined by a mismatch PCR-RFLP method. Aggressive PC was defined by diagnosis criteria of: Gleason score ≥8 and/or ≥T3 clinical stage and/or PSA ≥20ng/ ml. Results: The mean±SD age at diagnosis was 69.9±6.9 years (range, 47-90) for PC patients and 70.7±8.8 (range, 43-95) for non-PC patients (72.5±8.3 for BPH patients and 69.9±8.9 years for normal controls), showing no significant differences (p=0.11). 286 patients were classified with aggressive PC and 221 with non-aggressive PC. The rs1447295 A allele was associated with susceptibility to PC (PC versus non-PC: p=0.041; OR,1.28; 95%CI=1.01-1.61), and was more significantly associated with disease in aggressive PC (aggressive PC versus normal controls, p=0.013; OR,1.43; 95%CI=1.08-1.90). The rs6983267 G allele did not show significant association with susceptibility to PC (PC versus non-PC: p=0.967; OR,1.00; 95%CI=0.83-1.21). However, it was associated with disease in non-aggressive PC (non-aggressive PC versus normal controls: p=0.0068; OR,1.43; 95%CI=1.10-1.85). Conclusions: The two SNPs at 8q24 were associated with an increased risk of prostate cancer and contributed to tumor aggression in Japanese men. This supports the previous observation that 8q24 harbors significant genes contributing to the susceptibility of PC.

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Introduction & Objectives: Clinical features of prostate cancer (PCa) families and other malignancies associated with this disease are not well described. The aim of this study was to assess whether primary tumours other than PCa aggregate in Finnish families with PCa using large registry based family data with histologically confirmed cancer diagnoses and a follow up time of 40 years. Material & Methods: We calculated standardized incidence ratios (SIR) for 5539 members of 202 Finnish families with PCa, where the observed numbers of cancers were compared to site-spesific expected numbers based on the national cancer incidence rates. Information of family members was confirmed from population registry and cancer data from hospital records and Finnish Cancer Registry respectively. Multivariate cluster analysis was used to separate families with clinically aggressive disease to a separate analysis. Results: Significantly increased risk was observed for gastric carcinoma in women (SIR 1.81, 95% confidence interval 1.20-2.99). Males in the families with clinically aggressive disease had increased risk for gallbladder (SIR 4.05, 1.53-10.73) and small intestine carsinoma (SIR 5.88, 2.62-13.20) and females for liver carsinoma (SIR 4.76,1.54-14.86) and multiple myeloma (SIR 3.45, 1,11-10.7) and breast carcinoma (SIR 3.08, 1.16-8.21) in the the age group of 30-39 years. SIR of 0.90-1.79 (0.79-1.95) for overall cancer risk was observed for males and 0.98 (CI 0.85-1.12) for females. Conclusions: Our results suggest that in PCa families the risk for other cancers correlate with the clinical characteristics of PCa cases in family. In families with aggressive prostate cancer, an increased risk to other cancers was seen. However, in total set of PCa families no increase in cancer incidence of other cancers was seen in except for gastric carsinoma in females.

Eur Urol Suppl 2009;8(4):317