PDF file - 168K, SNP details by study.

PDF file - 67K, Descriptives for smoking, BMI, height, dietary variables, alcohol, sex, and NSAID use.

PDF file - 55K, Further information about main finding

PDF file - 96K, All GxE interactions stratified by cancer site.

PDF file - 55K, Study specific definitions of regular aspirin/NSAID use.

PDF file - 52K, Further information about main finding.

PDF file - 77K, All GxE interaction results.

PDF file - 52K, Forest plots for meta-analysis results with GxE interaction p < 0.01

Background: Observational studies have consistently associated obesity with colorectal cancer risk. Because both traits are genetically determined and share some metabolic biomarkers, we hypothesized that obesity-related polymorphisms could also influence the risk of developing colorectal cancer. Methods: We conducted a comprehensive population-based case–control study in 1,792 German colorectal cancer cases and 1,805 controls to explore associations between 28 obesogenic variants identified through genome-wide association studies (GWAS) and colorectal cancer risk. We also evaluated interactions between polymorphisms and body mass index (BMI), type II diabetes (T2D), and gender. Results: No evidence of association between obesogenic variants and colorectal cancer risk was observed after correction for multiple testing. There was only a remarkable interaction between the LTArs1041981 polymorphism and gender, which modified the risk of colorectal cancer [Pinteraction = 0.002; males: odds ratio (OR), 1.14; 95% confidence intervals (CI), 1.00–1.30 vs. females: OR, 0.83; 95% CI, 0.71–0.97]. Conclusions: Our findings showed that obesogenic variants are not a major pathogenetic risk factor for colorectal cancer. Impact: This comprehensive population-based case–control study does not provide evidence of a shared genetic component between obesity and colorectal cancer. Cancer Epidemiol Biomarkers Prev; 23(6); 1125–8. ©2014 AACR.

Background: Previous studies reported a positive association of body mass index (BMI) with microsatellite-stable (MSS) but not with microsatellite-instable (MSI-high) colorectal cancer. However, information from population-based studies conducted in representative age groups is so far limited. Methods: We conducted a population-based case–control study (DACHS) in Southern Germany, including 1,215 patients with incident colorectal cancer and 1,891 matched controls with no upper age limit. Information on risk factors of colorectal cancer was obtained in standardized interviews. Microsatellite instability was analyzed using a mononucleotide marker panel. Results: Median age among cases was 69 years, and 115 cases were classified MSI-high (9.5%). In multivariate analyses, BMI was positively associated with both risk of MSI-high colorectal cancer [per 5 kg/m2: OR, 1.71; 95% confidence interval (CI), 1.35–2.17] and risk of MSS colorectal cancer (OR, 1.20; 95% CI, 1.07–1.33). The association with MSI-high colorectal cancer was limited to women (OR, 2.04; 95% CI, 1.50–2.77; P interaction = 0.02) and most pronounced among ever users of postmenopausal hormone replacement therapy (OR, 4.68; 95% CI, 2.36–9.30; P interaction = 0.01). In case-only analyses, BMI was more strongly associated with MSI-high colorectal cancer than with MSS colorectal cancer among women (OR, 1.84; 95% CI, 1.13–1.82; P interaction = 0.01). Conclusions: This population-based study confirms previous findings of increased risk of MSS colorectal cancer with obesity between both sexes and suggests that overweight and obesity may also be associated with increased risk of MSI-high colorectal cancer among women. Impact: These findings extend available data on the association of BMI and microsatellite instability in colorectal cancer and may suggest a link between overweight and obesity with sporadic MSI-high colorectal cancer in women. Cancer Epidemiol Biomarkers Prev; 22(12); 2303–11. ©2013 AACR.

Abstract Genome-wide association studies (GWAS) have identified more than a dozen loci associated with colorectal cancer (CRC) risk. Here, we examined potential effect-modification between single-nucleotide polymorphisms (SNP) at 10 of these loci and probable or established environmental risk factors for CRC in 7,016 CRC cases and 9,723 controls from nine cohort and case–control studies. We used meta-analysis of an efficient empirical-Bayes estimator to detect potential multiplicative interactions between each of the SNPs [rs16892766 at 8q23.3 (EIF3H/UTP23), rs6983267 at 8q24 (MYC), rs10795668 at 10p14 (FLJ3802842), rs3802842 at 11q23 (LOC120376), rs4444235 at 14q22.2 (BMP4), rs4779584 at 15q13 (GREM1), rs9929218 at 16q22.1 (CDH1), rs4939827 at 18q21 (SMAD7), rs10411210 at 19q13.1 (RHPN2), and rs961253 at 20p12.3 (BMP2)] and select major CRC risk factors (sex, body mass index, height, smoking status, aspirin/nonsteroidal anti-inflammatory drug use, alcohol use, and dietary intake of calcium, folate, red meat, processed meat, vegetables, fruit, and fiber). The strongest statistical evidence for a gene–environment interaction across studies was for vegetable consumption and rs16892766, located on chromosome 8q23.3, near the EIF3H and UTP23 genes (nominal Pinteraction = 1.3 × 10−4; adjusted P = 0.02). The magnitude of the main effect of the SNP increased with increasing levels of vegetable consumption. No other interactions were statistically significant after adjusting for multiple comparisons. Overall, the association of most CRC susceptibility loci identified in initial GWAS seems to be invariant to the other risk factors considered; however, our results suggest potential modification of the rs16892766 effect by vegetable consumption. Cancer Res; 72(8); 2036–44. ©2012 AACR.

ATP Binding Cassette B1 (ABCB1) is a transporter with a broad substrate specificity involved in the elimination of several carcinogens from the gut. Several polymorphic variants within the ABCB1 gene have been reported as modulators of ABCB1-mediated transport. We investigated the impact of ABCB1 genetic variants on colorectal cancer (CRC) risk. A hybrid tagging/functional approach was performed to select 28 single nucleotide polymorphisms (SNPs) that were genotyped in 1,321 Czech subjects, 699 CRC cases and 622 controls. In addition, six potentially functional SNPs were genotyped in 3,662 German subjects, 1,809 cases and 1,853 controls from the DACHS study. We found that three functional SNPs (rs1202168, rs1045642 and rs868755) were associated with CRC risk in the German population. Carriers of the rs1202168_T and rs868755_T alleles had an increased risk for CRC (P(trend) = 0.016 and 0.029, respectively), while individuals bearing the rs1045642_C allele showed a decreased risk of CRC (P(trend) = 0.022). We sought to replicate the most significant results in an independent case-control study of 3,803 subjects, 2,169 cases and 1,634 controls carried out in the North of Germany. None of the SNPs tested were significantly associated with CRC risk in the replication study. In conclusion, in this study of about 8,800 individuals we show that ABCB1 gene polymorphisms play at best a minor role in the susceptibility to CRC.

Colorectal cancer is the second leading cause of cancer death in developed countries. Genome-wide association studies (GWAS) have successfully identified novel susceptibility loci for colorectal cancer. To follow up on these findings, and try to identify novel colorectal cancer susceptibility loci, we present results for GWAS of colorectal cancer (2,906 cases, 3,416 controls) that have not previously published main associations. Specifically, we calculated odds ratios and 95% confidence intervals using log-additive models for each study. In order to improve our power to detect novel colorectal cancer susceptibility loci, we performed a meta-analysis combining the results across studies. We selected the most statistically significant single nucleotide polymorphisms (SNPs) for replication using ten independent studies (8,161 cases and 9,101 controls). We again used a meta-analysis to summarize results for the replication studies alone, and for a combined analysis of GWAS and replication studies. We measured ten SNPs previously identified in colorectal cancer susceptibility loci and found eight to be associated with colorectal cancer (p value range 0.02 to 1.8 × 10−8). When we excluded studies that have previously published on these SNPs, five SNPs remained significant at p < 0.05 in the combined analysis. No novel susceptibility loci were significant in the replication study after adjustment for multiple testing, and none reached genome-wide significance from a combined analysis of GWAS and replication. We observed marginally significant evidence for a second independent SNP in the BMP2 region at chromosomal location 20p12 (rs4813802; replication p value 0.03; combined p value 7.3 × 10−5). In a region on 5p33.15, which includes the coding regions of the TERT-CLPTM1L genes and has been identified in GWAS to be associated with susceptibility to at least seven other cancers, we observed a marginally significant association with rs2853668 (replication p value 0.03; combined p value 1.9 × 10−4). Our study suggests a complex nature of the contribution of common genetic variants to risk for colorectal cancer.

BACKGROUND:The link between colorectal cancer (CRC) and type 2 diabetes mellitus (T2D) has been extensively studied. Although it is commonly accepted that T2D is a risk factor for CRC, the underlying mechanisms are still poorly understood. RESEARCH DESIGN AND METHODS:Given that the genetic background contributes to both traits, it is conceivable that genetic variants associated with T2D may also influence the risk of CRC. We selected 26 T2D-related single-nucleotide polymorphisms (SNP) previously identified by genome-wide association studies and assessed their association with CRC and their interaction with known risk factors (gender, T2D, and body mass index) of CRC. Selected SNP were genotyped in 1798 CRC cases and 1810 controls from the population-based Darmkrebs: Chancen der Verhütung durch Screening (DACHS) study (Germany). RESULTS:Patients carrying the TCF7L2_rs7903146_T allele had an increased risk of CRC (P(trend) = 0.02), whereas patients harboring the IL13_rs20541_T allele had a reduced risk (P(trend) = 0.02). A further analysis revealed gender-specific effects: the TCF7L2_rs7903146_T allele was associated with an increased risk of CRC in women (P(trend) = 0.003) but not in men (P(interaction) = 0.06); the LTA_rs1041981_A allele was associated with a decreased risk for CRC in women (P(trend) = 0.02), with an opposite effect in men (P(trend) = 0.05; P(interaction) = 0.002); the CDKAL1_rs7754840_C allele was associated with a decreased risk for CRC in men (P(trend) = 0.03), with no effect in women (P(interaction) = 0.03). The risk associated with the presence of T2D was modified both by IGF2BP2_rs4402960 and PPARγ_rs1801282 SNP (P(interaction) = 0.04 and 0.04, respectively). None of the findings were significant after correction for multiple comparisons. CONCLUSIONS:These findings suggest that T2D-related variants modify CRC risk independently and/or in an interactive manner according to the gender and the presence or absence of T2D.

Research Design and Methods: Given that the genetic background contributes to both traits, it is conceivable that genetic variants associated with T2D may also influence the risk of CRC. We selected 26 T2D-related single-nucleotide polymorphisms (SNP) previously identified by genomewide association studies and assessed their association with CRC and their interaction with known risk factors (gender, T2D, and body mass index) of CRC. Selected SNP were genotyped in 1798 CRC cases and 1810 controls from the population-based Darmkrebs: Chancen der Verhütung durch Screening (DACHS) study (Germany).

BACKGROUND:Recent studies have reported associations of DNA repair pathway gene variants and risk of various cancers and precancerous lesions, such as chronic atrophic gastritis (CAG).METHODS:A nested case-control study within the German population-based ESTHER cohort was conducted, including 533 CAG cases and 1054 controls. Polymorphisms in eleven DNA repair genes (APEX1, ERCC1, ERCC2/XPD, PARP1 and XRCC1), in CD3EAP/ASE-1 and PPP1R13L were analysed.RESULTS:No association was disclosed for any of the analysed polymorphisms. Nor did stratified analyses according to ages < 65 and ≥ 65 years show any significant association with CAG risk.CONCLUSIONS:The results of this large German case-control study do not reveal associations of DNA repair pathway polymorphisms and risk of CAG. On the basis of a large number of CAG cases, they do not support associations of DNA repair pathway SNPs with CAG risk, but suggest the need of larger studies to disclose or exclude potential weak associations, or of studies with full coverage of candidate genes.

Background Using the Breast Cancer Association Consortium, the authors previously reported that the single nucleotide polymorphism 7q21-rs6964587 (AKAP9-M463I) is associated with breast cancer risk. The authors have now assessed this association more comprehensively using 16 independent case–control studies. Methods The authors genotyped 14 843 invasive case patients and 19 852 control subjects with white European ancestry and 2595 invasive case patients and 2192 control subjects with Asian ancestry. ORs were estimated by logistic regression, adjusted for study. Heterogeneity in ORs was assessed by fitting interaction terms or by subclassifying case patients and applying polytomous logistic regression. Results For white European women, the minor T allele of 7q21-rs6964587 was associated with breast cancer risk under a recessive model (OR 1.07, 95% CI 1.00 to 1.13, p=0.04). Results were inconclusive for Asian women. From a combined analysis of 24 154 case patients and 33 376 control subjects of white European ancestry from the present and previous series, the best-fitting model was recessive, with an estimated OR of 1.08 (95% CI 1.03 to 1.13, p=0.001). The OR was greater at younger ages (p trend=0.01). Conclusion This may be the first common susceptibility allele for breast cancer to be identified with a recessive mode of inheritance.

The mechanisms underlying the association of menopausal hormone therapy (MHT) with reduced colorectal cancer (CRC) risk are unknown and the identification of genetic modifiers may yield further insight. We explored the effect modification of MHT-associated CRC risk in postmenopausal women by 47 polymorphisms with known or putative functional relevance in 16 candidate genes related to hormone metabolism (COMT, CYP1A1, CYP1A2, CYP1B1, CYP2C9, CYP2C19, CYP3A4, CYP17A1, GSTP, and HSD17B1), transport (ABCB1), and signaling (ESR1, ESR2, SHBG, PGR, and NR1I2). A total of 685 CRC patients and 684 healthy controls from a German population-based case-control study (DACHS) were genotyped. Multiplicative statistical interaction between polymorphisms and ever MHT use as well as duration of use was assessed using multivariate logistic regression. CRC risk associated with ever MHT use as well as with duration was significantly modified by rs1202168 in the transporter gene ABCB1 (P interaction=0.04). The MHT-associated risk reduction was not significant in homozygous non-carriers (odds ratio (OR) ever use=0.84, 95% confidence interval (CI) 0.53-1.34; OR per 5 year duration=0.94, 95% CI 0.83-1.08), while homozygous carriers of the minor T allele had a 57% lower risk with ever use of MHT (95% CI 0.21-0.88) and a 22% lower risk per 5 years of MHT use (95% CI 0.62-0.97). Significant effect modification was also observed for the ESR1_rs910416 polymorphism (P interaction=0.03 for ever use and 0.07 for duration of use), whereby the decreased risk was attenuated in homozygous carriers of the minor C allele (OR ever use=0.87, 95% CI 0.48-1.60, OR per 5 year duration=0.99, 95% CI 0.83-1.18). Results of this exploratory study provide first evidence that polymorphisms in genes related to estrogen transport and signaling may modify MHT-associated CRC risk but warrant replication in an independent population.

Mucins represent major components of the mucous layer in the stomach, protecting the underlying epithelium from acid, mechanical trauma, proteases and pathogenic bacteria. Previous studies have shown an association of neoplastic transformation in the stomach with aberrant mucin levels, suggesting a potential role of genetic variation in mucin genes in the development of gastric cancer (GC). We assessed the association of genetic variation in candidate single nucleotide polymorphisms (SNPs) in mucin genes with the risk of chronic atrophic gastritis (CAG), a well-established precursor of GC in the German population-based ESTHER study. We genotyped MUC1 T31T, MUC2 L58P, MUC2 V116M, MUC5B E34G, MUC5B R51W, MUC5B rs2014486 (intronic) and MUC6 V619M for 533 serologically defined CAG cases and 1054 age- and sex-matched controls. None of the analysed SNPs was associated with CAG. However, large studies are needed to disclose or exclude potential weak associations of these SNPs with CAG risk.

Introduction Menopausal hormone therapy (MHT) has been associated with reduced colorectal cancer (CRC) risk. Since the underlying biological mechanisms of MHT effects on CRC are unknown, we investigated whether single nucleotide polymorphisms (SNPs) in genes related to sex steroid metabolism, transport and signalling modify MHT-associated CRC risk. Methods 47 SNPs in 16 candidate genes related to sex steroid transport (ABCB1), metabolism (COMT, CYP1A1, CYP1A2, CYP1B1, CYP2C9, CYP2C19, CYP3A4, CYP17A1, GSTP, HSD17B1) and signalling (ESR1, ESR2, SHBG, PGR, NR1I2) were genotyped using genomic DNA samples from 685 female postmenopausal CRC patients and 684 controls without CRC of a German population-based case-control study (DACHS). Unconditional multivariate logistic regression was performed and effect modification was assessed using a multiplicative interaction term. Results CRC risk associated with ever MHT use as well as with duration was significantly modified by rs1202168 in ABCB1 (p interaction =0.04). The MHT-associated risk reduction was no longer significant in homozygous non-carriers, while homozygous carriers of the minor T allele had a 57% lower risk with ever use of MHT and a 22% lower risk per 5 years of MHT use. Significant effect modification was also observed for rs910416 in ESR1, whereby the decreased CRC risk was attenuated in carriers of the minor C allele (p interaction =0.03 for ever use and 0.07 for duration of use). Conclusion Our results provide the first evidence that polymorphisms in sex steroid-related genes may modify CRC risk associated with MHT. Our findings warrant replication in independent study populations.