Prostate Cancer and Prostatic Diseases (2015) 18, 310–316 © 2015 Macmillan Publishers Limited All rights reserved 1365-7852/15 www.nature.com/pcan ORIGINAL ARTICLE Genetic variants in the TEP1 gene are associated with prostate cancer risk and recurrence CGu1,2,8,QLi2,3,4,8, Y Zhu1,2,8,YQu1,2, G Zhang1,2, M Wang2,3, Y Yang5,6, J Wang5,6, L Jin5,6,QWei3,7 and D Ye1,2 BACKGROUND: Telomere-related genes play an important role in carcinogenesis and progression of prostate cancer (PCa). It is not fully understood whether genetic variations in telomere-related genes are associated with development and progression in PCa patients. METHODS: Six potentially functional single-nucleotide polymorphisms (SNPs) of three key telomere-related genes were evaluated in 1015 PCa cases and 1052 cancer-free controls, to test their associations with risk of PCa. Among 426 PCa patients who underwent radical prostatectomy (RP), the prognostic significance of the studied SNPs on biochemical recurrence (BCR) was also assessed using the Kaplan–Meier analysis and Cox proportional hazards regression model. The relative telomere lengths (RTLs) were measured in peripheral blood leukocytes using real-time PCR in the RP patients. RESULTS: TEP1 rs1760904 AG/AA genotypes were significantly associated with a decreased risk of PCa (odds ratio (OR): 0.77, 95% confidence interval (CI): 0.64–0.93, P = 0.005) compared with the GG genotype. By using median RTL as a cutoff level, RP patients with TEP1 rs1760904 AG/AA genotypes tended to have a longer RTL than those with the GG genotype (OR: 1.55, 95% CI: 1.04–2.30, P = 0.031). A significant interaction between TEP1 rs1713418 and age in modifying PCa risk was observed (P = 0.005). After adjustment for clinicopathologic risk factors, the presence of heterozygotes or rare homozygotes of TEP1 rs1760904 and TNKS2 rs1539042 were associated with BCR in the RP cohorts (hazard ratio: 0.53, 95% CI: 0.36–0.79, P = 0.002 and hazard ratio: 1.67, 95% CI: 1.07–2.48, P = 0.017, respectively). CONCLUSIONS: These data suggest that genetic variations in the TEP1 gene may be biomarkers for risk of PCa and BCR after RP. Prostate Cancer and Prostatic Diseases (2015) 18, 310–316; doi:10.1038/pcan.2015.27; published online 4 August 2015 INTRODUCTION to the end-replication problem.8 Progressive telomere shortening Although prostate cancer (PCa) is the second most commonly from cell division provides a barrier for tumor progression. diagnosed cancer and the sixth most common cause of cancer- Mounting evidence indicates that by initiating chromosomal related mortality among men worldwide,1 only 10%–20% of instability, short and dysfunctional telomeres may be involved 9 diagnosed cases die from the disease,2 whereas more patients in prostate carcinogenesis. In addition to be involved in PCa live to develop recurrences. Patients with localized and locally development, telomeres may also have a role in disease advanced PCa are frequently treated with radical prostatec- progression and tumor telomere alteration may prove to be a – tomy (RP). However, it is estimated that 430% of men under- useful prognostic marker of post-prostatectomy BCR.10 12 going RP will have disease relapse, also referred to as biochemical Theoretically, functional genetic variants that affect telomere recurrence (BCR), defined as the first clinical indication of a rising elongation, activation of telomerase and configuration of telo- serum level of PSA.3 The risk of disease development greatly meric proteins could lead to some accelerated functional changes differs among individuals, and the heterogeneity in clinical responsible for cancer development and further growth advan- behavior despite similar clinicopathologic characteristics further tages. Cancer genome-wide association studies have shown emphasizes the need to identify novel markers for recurrence.4 that single-nucleotide polymorphisms (SNPs) in the telomere- – Germline variation has been associated with risk of PCa and the related genes are associated with risk of various cancers.13 15 In recent use of genetic information to predict outcome and to guide addition, previous studies have identified several PCa suscept- treatment has also been steadily increasing in oncologic research ibility loci located in the telomerase reverse transcriptase (TERT) and practice.5 gene, the catalytic subunit of the telomerase ribonucleoprotein Telomeres are terminal, tandem nucleotide repeats (5′-TTAGGG-3′), complex.16,17 However, the impact of functional genetic variants in complex with telomere-binding proteins located at the ends of associated with PCa risk and recurrence in other telomere-related every chromosome, and are key components in the maintenance genes remains unclear. of chromosomal stability.6,7 In somatic cells, telomeres are There are two telomere-length maintenance mechanisms, shortening by 30–200 base pairs after each mitotic division due including telomerase-based and alternative lengthening of 1Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China; 2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China; 3Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China; 4Department of Pathology, First Affiliated Hospital, Xinjiang Medical University, Urumqi, China; 5Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; 6Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China and 7Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA. Correspondence: Dr Q Wei, Cancer Institute, Fudan University Shanghai Cancer Center, 270 Dong An Road, Shanghai 200032, China or Dr D Ye, Department of Urology, Fudan University Shanghai Cancer Center, 270 Dong An Road, Shanghai 200032, China. E-mail: [email protected] or [email protected] 8These authors contributed equally to this work. Received 11 September 2014; revised 8 April 2015; accepted 13 April 2015; published online 4 August 2015 TEP1 polymorphisms and prostate cancer CGuet al 311 telomeres recombinational mechanisms. TEP1 is a key component Patients were treated with radiation, androgen deprivation therapy and of the telomerase ribonucleoprotein complex, responsible for RP. A subset of clinically localized PCa patients who underwent RP (n = 441) telomerase activity.18 TEP1 also interacts directly with Bloom between 2006 and 2009 were followed up by PSA at least every 3 months syndrome protein and modulates its helicase activity, suggesting and disease-management information available from medical records; that TEP1 has an important function in the alternative lengthening subjects were excluded if their medical records were not available (n = 15). 19 The median follow-up time of the entire patient cohort was 37.7 months. of telomere pathways. TNKS and TNKS2 enhance the access of BCR was defined as two consecutive PSA measurements 40.2 ng ml − 1 at telomerase to telomeres, thereby having a role in telomere 4 fi 20 an interval of 3 months and the date of this event was set to the rst of maintenance. Variants in TEP1 and TNKS have also been found to these two test occasions.25 This study was approved by the Institutional 21,22 be regulators of telomere length. Review Board of Fudan University Shanghai Cancer Center. Thus, we designed a case–control study using a candidate-gene approach, to test the hypothesis that potentially functional SNP selection and genotyping polymorphisms in three key telomere-related genes (TEP1, TNKS We searched the National Center for Biotechnology Information dbSNP and TNKS2), which have previously been related to telomere database (http://www.ncbi.nlm.nih.gov/) for potentially functional SNPs length are associated with PCa risk. The relationship between and SNPinfo (http://snpinfo.niehs.nih.gov/), to identify the candidate SNPs these SNPs and BCR were further tested among a subset of based on the following three criteria: (1) located at the regulatory or patients who received RP. coding region of genes (that is, the 5′-near gene, 5′-untranslated regions (UTRs), exons, splice sites, 3′-UTR and 3′-near gene); (2) the minor allele frequency ⩾ 5% in Chinese Han, Beijing descendants reported in HapMap; MATERIALS AND METHODS (3) affecting the activities of microRNA-binding sites in the 3′-UTR and Study design and population transcription factor binding sites in the putative promoter region or changing the amino acid in the exons. The study subjects were mostly from previously published case–control For the TEP1 gene, we chose rs1713418 and rs1760904; the former is study.23 Briefly, 1115 eligible patients recruited into this study were newly located in the 3′-UTR region and the latter is located in the exon region. diagnosed and histopathologically confirmed primary prostate adenocar- For the TNKS gene, we chose rs17734024 and rs1055328, both located in cinoma from Fudan University Shanghai Cancer Center between January the 3′-UTR region. For the TNKS2 gene, we chose rs1539042 and 2005 and January 2012, of whom 1015 (92%) agreed to participate in this rs3758499; the former is located in the 3′-UTR region and the latter is study (Figure 1). All cases had received no prior chemotherapy or located in the exon region. All these six selected SNPs were genotyped by radiotherapy on recruitment. The tumor stage was determined according the TaqMan real-time PCR method as described previously.26 Briefly, DNA to criteria established by the American Joint Committee