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// Cornelia Zochmeister 1, * , Stefanie Brezina 1, * , Philipp Hofer 1 , Andreas Baierl 2 , Michael M. Bergmann 3 , Thomas Bachleitner-Hofmann 3 , Judith Karner-Hanusch 3 , Anton Stift 3 , Armin Gerger 4 , Gernot Leeb 5 , Karl Mach 5 , Sivaramakrishna Rachakonda 6 , Rajiv Kumar 6 and Andrea Gsur 1 1 Medical University Vienna, Department of Medicine I, Institute of Cancer Research, Vienna, Austria 2 University of Vienna, Department of Statistics and Operations Research, Vienna, Austria 3 Medical University Vienna, Department of Surgery, Vienna, Austria 4 Medical University of Graz, Division of Oncology, Department of Internal Medicine, Graz, Austria 5 Hospital Oberpullendorf, Burgenland, Austria 6 German Cancer Research Center, Division of Molecular Genetic Epidemiology, Heidelberg, Germany * These authors have contributed equally to this work Correspondence to: Andrea Gsur, email: andrea.gsur@meduniwien.ac.at Keywords: telomere length; colorectal cancer; adenoma; cancer epidemiology Received: September 08, 2017 Accepted: January 31, 2018 Published: February 07, 2018 ABSTRACT Considering the high prevalence of colorectal cancer (CRC) and relatively high mortality there is strong interest in identification of clinically relevant biomarkers. Telomere shortening is supposed to contribute to genomic instability and crucially involved in process of carcinogenesis. Peripheral blood leukocyte (PBL) telomere length was previously investigated in several studies as potential biomarker for CRC but with controversial results. This prompted us to investigate relative PBL telomere length in association with different histological findings throughout the continuum of colorectal carcinogenesis in order to reflect the whole spectrum of putative CRC development in a large study involving 2011 individuals. The study based on the Colorectal Cancer Study of Austria (CORSA), including 384 CRC cases as well as age- and gender-matched 544 high-risk adenomas, 537 low-risk adenoma patients and 546 colonoscopy-negative controls. Relative expression of telomeric repeats and the single copy reference gene, albumin (T/S ratio) was determined using monochrome multiplex quantitative PCR (MMQPCR). Telomeres were found to be significantly longer in CRC patients compared to control subjects ( P = 3.61x10 -6 ). Yet, no significant differences in telomere length could be detected for high-risk ( P = 0.05956) and low-risk colorectal adenoma patients ( P = 0.05224). In addition, results presented in this manuscript highlight the impact of various epidemiological factors on PBL telomere length and its involvement in CRC. However, further large studies also including colorectal adenomas are necessary to confirm these results.

Most genome-wide association studies (GWAS) were analyzed using single marker tests in combination with stringent correction procedures for multiple testing. Thus, a substantial proportion of associated single nucleotide polymorphisms (SNPs) remained undetected and may account for missing heritability in complex traits. Model selection procedures present a powerful alternative to identify associated SNPs in high-dimensional settings. In this GWAS including 1060 colorectal cancer cases, 689 cases of advanced colorectal adenomas and 4367 controls we pursued a dual approach to investigate genome-wide associations with disease risk applying both, single marker analysis and model selection based on the modified Bayesian information criterion, mBIC2, implemented in the software package MOSGWA. For different case-control comparisons, we report models including between 1-14 candidate SNPs. A genome-wide significant association of rs17659990 (P=5.43x10(-9), DOCK3, chromosome 3p21.2) with colorectal cancer risk was observed. Furthermore, 56 SNPs known to influence susceptibility to colorectal cancer and advanced adenoma were tested in a hypothesis-driven approach and several of them were found to be relevant in our Austrian cohort. After correction for multiple testing (alpha=8.9x10(-4)), the most significant associations were observed for SNPs rs10505477 (P=6.08x10(-4)) and rs6983267 (P=7.35x10(-4)) of CASC8, rs3802842 (P=8.98x10(-5), COLCA1,2), and rs12953717 (P=4.64x10(-4), SMAD7). All previously unreported SNPs demand replication in additional samples. Reanalysis of existing GWAS datasets using model selection as tool to detect SNPs associated with a complex trait may present a promising resource to identify further genetic risk variants not only for colorectal cancer.

Human telomerase reverse transcriptase (TERT) gene encodes the catalytic subunit of telomerase and is located on chromosome 5p15, a genomic region which was found to be associated with multiple cancer types. But no associations with colorectal cancer (CRC) have been reported until recently. Therefore, the purpose of this study was to investigate the influence of seven single-nucleotide polymorphisms (SNPs) of TERT on susceptibility to colorectal polyps and CRC. The study population of our ongoing colorectal cancer study of Austria (CORSA) comprised 3,842 Caucasian participants. A total of 3,264 participants was genotyped including 142 CRC cases, 492 high-risk polyps, 837 low-risk polyps, and 1,793 polyp-free controls verified by colonoscopy. Genotyping was performed by TaqMan assay using genomic DNA. The impact of each SNP was estimated by multiple logistic regression analyses performed with R Version 2.11.1. None of the investigated TERT SNPs (rs2736122, rs2853676, rs2735940, rs2736098, rs2075786, rs2736100, rs4975605) were found to be associated with risk of CRC nor colonic polyps. However, the haplotype CGTATGG was associated with a significantly increased risk of high-risk polyps (OR = 1.48, 95% CI 1.01-2.17, P = 0.043). In accordance with other studies our results suggest no major influence of the investigated TERT SNPs on CRC and colorectal polyp risk. However, relevance of telomerase in tumorigenesis of multiple malignancies demands further investigations of the 5p15 locus concerning CRC susceptibility.

Background : X-ray repair cross complementation group 1 (XRCC1) plays a key role in base excision repair. The purpose of this study was to examine the association of two genetic polymorphisms in XRCC1 (rs1799782 and rs25487) with risk of colorectal polyps and colorectal cancer (CRC). Methods : In the ongoing colorectal cancer study of Austria (CORSA), a total of 3091 Caucasian participants was genotyped using 5′-nuclease TaqMan assays. Multiple logistic regression was applied to compare individuals of the control group against three different case groups namely CRC cases, high-risk and low-risk polyps. Results : The two investigated SNPs in XRCC1 were not found to be associated with neither CRC risk nor polyp risk. Comparing the CRC cases versus the controls the OR was 0.60 (95%CI 0.27–1.31) for the heterozygous polymorphic genotype of SNP rs1799782 and 1.47 (95%CI 0.81–2.65) for the homozygous polymorphic genotype of SNP rs25487. Comparing the high-risk polyp group versus the controls the OR was 2.64 (95%CI 0.61–11.42) for the homozygous polymorphic genotype of SNP rs1799782 and 0.89 (95%CI 0.60–1.33) for SNP rs25487, respectively. In an haplotype analysis also no statistically significant association was found. Conclusion : Our finding that none of the two investigated SNPs of XRCC1 were significantly associated with risk of CRC or polyps is consistent with the results of a recently published meta-analysis.

An einem Krankengut von 128 Patienten wird in einer retrospektiven Studie uber eine Methode der Prophylaxe und Therapie des postoperativen Ileus durch die temporare innere Dunndarmschienung nachSauer in eigener Modifikation berichtet. Das Verfahren besteht in einer Schienung des Dunndarmes mittels eines Silikonschlauches, wobei die Schiene uber eine Gastrostomie bzw. Zokostomie herausgeleitet wird. Durch die Schienung wird der Dunndarm in seinem physiologischen Windungsverlauf fixiert. Zusatzlich ist die freie Durchgangigkeit des Darmlumens gewahrleistet. Das Schienungsrisiko betragt 3,1%, die Ileusrezidivquote betragt 0,78%. Die Letalitat der Schienung betragt 0,78%. Wir empfehlen die Methode zur Prophlaxe und Therapie des Ileus, es konnen aber nur prospektive, randomisierte Studien das Schienungsrisiko exakt beurteilen.

Purpose Insulin-like growth factor 1 (IGF1) is a peptide growth factor that promotes cell proliferation and inhibits apoptosis. The bioavailability of IGF1 is regulated by the insulin-like growth factor binding protein 3 (IGFBP3). The purpose of this study was to examine the association of genetic variants in IGF1 (rs6214, rs6220, and rs35767) and IGFBP3 (rs2854744 and rs2854746) with risk of colorectal polyps and colorectal cancer. Methods In this ongoing colorectal cancer study of Austria (CORSA), a total of 3,360 Caucasian participants, consisting of 178 colorectal cancer patients, 328 patients with high risk polyps, 1,059 patients with low risk colorectal polyps, and 1,795 colonoscopy-negative controls, were recruited within a large colorectal screening project in the province Burgenland and from three hospitals in Vienna. Multiple logistic regression was applied to compare individuals of the control group against three different risk groups, namely, colorectal cancer group, high risk polyp group, and low risk polyp group. Results Carriers of the homozygous polymorphic genotype of the SNP rs6214 were associated with an increased colorectal risk (OR = 1.79, 95% CI 1.04–1.90) compared to the colonoscopy-negative controls; this was also found when combining colorectal cancer cases and high risk polyp group (OR = 1.39, 95% CI 1.01–1.90). Conclusion Our results suggest that the SNP rs6214 of IGF1 could have an impact on developing colorectal cancer and colorectal polyps with villous elements.

Telomerase reactivation and expression of human telomerase gene [human telomerase reverse transcriptase (hTERT)] are hallmarks of unlimited proliferation potential of cancer cells. A polymorphic tandem repeats minisatellite of hTERT gene, termed MNS16A was reported to influence hTERT expression. To assess the role of MNS16A as potential biomarker for colorectal cancer (CRC), we investigated for the first time the association of MNS16A genotypes with risk of colorectal polyps and CRC. In the ongoing colorectal cancer study of Austria (CORSA), 3842 Caucasian participants were recruited within a large screening project in the province Burgenland including 90 CRC cases, 308 high-risk polyps, 1022 low-risk polyps and 1822 polyp free controls verified by colonoscopy. MNS16A genotypes were determined by polymerase chain reaction from genomic DNA. Associations of MNS16A genotypes with CRC risk were estimated by logistic regression analysis computing odds ratios (ORs) and 95% confidence intervals (CIs). We identified five different variable number of tandem repeats (VNTRs) of MNS16A including VNTR-364, a newly discovered rare variant. VNTR-274 allele was associated with a 2.7-fold significantly increased risk of CRC compared with the VNTR-302 wild-type (OR = 2.69; 95% CI = 1.11–6.50; P = 0.028). In our CORSA study, the medium length VNTR-274 was identified as risk factor for CRC. Although, this population-based study herewith reports the largest cohort size concerning MNS16A thus far, further large-scale studies in diverse populations are warranted to confirm hTERT MNS16A genotype as potential biomarker for assessment of CRC risk.