Publications by authors named "David Duggan"

153 Publications

Genetic architectures of proximal and distal colorectal cancer are partly distinct.

Gut 2021 Jul 25;70(7):1325-1334. Epub 2021 Feb 25.

Cancer Prevention and Control Program, Catalan Institute of Oncology - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain.

Objective: An understanding of the etiologic heterogeneity of colorectal cancer (CRC) is critical for improving precision prevention, including individualized screening recommendations and the discovery of novel drug targets and repurposable drug candidates for chemoprevention. Known differences in molecular characteristics and environmental risk factors among tumors arising in different locations of the colorectum suggest partly distinct mechanisms of carcinogenesis. The extent to which the contribution of inherited genetic risk factors for CRC differs by anatomical subsite of the primary tumor has not been examined.

Design: To identify new anatomical subsite-specific risk loci, we performed genome-wide association study (GWAS) meta-analyses including data of 48 214 CRC cases and 64 159 controls of European ancestry. We characterised effect heterogeneity at CRC risk loci using multinomial modelling.

Results: We identified 13 loci that reached genome-wide significance (p<5×10) and that were not reported by previous GWASs for overall CRC risk. Multiple lines of evidence support candidate genes at several of these loci. We detected substantial heterogeneity between anatomical subsites. Just over half (61) of 109 known and new risk variants showed no evidence for heterogeneity. In contrast, 22 variants showed association with distal CRC (including rectal cancer), but no evidence for association or an attenuated association with proximal CRC. For two loci, there was strong evidence for effects confined to proximal colon cancer.

Conclusion: Genetic architectures of proximal and distal CRC are partly distinct. Studies of risk factors and mechanisms of carcinogenesis, and precision prevention strategies should take into consideration the anatomical subsite of the tumour.
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http://dx.doi.org/10.1136/gutjnl-2020-321534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223655PMC
July 2021

Effects of Immunization With the Soil-Derived Bacterium on Stress Coping Behaviors and Cognitive Performance in a "Two Hit" Stressor Model.

Front Physiol 2020 5;11:524833. Epub 2021 Jan 5.

Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States.

Previous studies demonstrate that NCTC 11659 (), a soil-derived bacterium with anti-inflammatory and immunoregulatory properties, is a potentially useful countermeasure against negative outcomes to stressors. Here we used male C57BL/6NCrl mice to determine if repeated immunization with is an effective countermeasure in a "two hit" stress exposure model of chronic disruption of rhythms (CDR) followed by acute social defeat (SD). On day -28, mice received implants of biotelemetric recording devices to monitor 24-h rhythms of locomotor activity. Mice were subsequently treated with a heat-killed preparation of (0.1 mg, administered subcutaneously on days -21, -14, -7, and 27) or borate-buffered saline vehicle. Mice were then exposed to 8 consecutive weeks of either stable normal 12:12 h light:dark (LD) conditions or CDR, consisting of 12-h reversals of the LD cycle every 7 days (days 0-56). Finally, mice were exposed to either a 10-min SD or a home cage control condition on day 54. All mice were exposed to object location memory testing 24 h following SD. The gut microbiome and metabolome were assessed in fecal samples collected on days -1, 48, and 62 using 16S rRNA gene sequence and LC-MS/MS spectral data, respectively; the plasma metabolome was additionally measured on day 64. Among mice exposed to normal LD conditions, immunization with induced a shift toward a more proactive behavioral coping response to SD as measured by increases in scouting and avoiding an approaching male CD-1 aggressor, and decreases in submissive upright defensive postures. In the object location memory test, exposure to SD increased cognitive function in CDR mice previously immunized with . Immunization with stabilized the gut microbiome, attenuating CDR-induced reductions in alpha diversity and decreasing within-group measures of beta diversity. Immunization with also increased the relative abundance of 1-heptadecanoyl-sn-glycero-3-phosphocholine, a lysophospholipid, in plasma. Together, these data support the hypothesis that immunization with stabilizes the gut microbiome, induces a shift toward a more proactive response to stress exposure, and promotes stress resilience.
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http://dx.doi.org/10.3389/fphys.2020.524833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7813891PMC
January 2021

Calibration of polygenic risk scores is required prior to clinical implementation: results of three common cancers in UKB.

J Med Genet 2020 Dec 21. Epub 2020 Dec 21.

Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, Illinois, USA

Background: SNP-based polygenic risk scores have recently been adopted in the clinic for risk assessment of some common diseases. Their validity is supported by a consistent trend between their and disease risk in populations. However, for clinical use at the individual level, the reliability of is necessary considering they are directly used to calculate remaining lifetime risk.

Objectives: We assessed the reliability of polygenic score values to estimate prostate cancer (PCa), breast cancer (BCa) and colorectal cancer (CRC) risk in three incident cohorts from the UK Biobank (n>500 000).

Methods: Cancer-specific Genetic Risk Score (GRS), a well-established population-standardised polygenic risk score, was calculated.

Results: A systematic bias was found between estimated risks (GRS values) and observed risks; β (95% CI) was 0.67 (0.58-0.76), 0.74 (0.65-0.84) and 0.82 (0.75-0.89), respectively, for PCa, BCa and CRC, all significantly lower than 1.00 (perfect calibration), p<0.001. After applying a correction factor derived from a training data set, the β for corrected GRS values in an independent testing data set were 1.09 (1.05-1.13), 1.00 (0.88-1.12) and 1.08 (0.96-1.21), respectively, for PCa, BCa and CRC.

Conclusion: Assessing the calibration of polygenic risk scores is necessary and feasible to ensure their reliability prior to clinical implementation.
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http://dx.doi.org/10.1136/jmedgenet-2020-107286DOI Listing
December 2020

Performance of Three Inherited Risk Measures for Predicting Prostate Cancer Incidence and Mortality: A Population-based Prospective Analysis.

Eur Urol 2021 03 28;79(3):419-426. Epub 2020 Nov 28.

Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, IL, USA. Electronic address:

Background: Single nucleotide polymorphism-based genetic risk score (GRS) has been developed and validated for prostate cancer (PCa) risk assessment. As GRS is population standardized, its value can be interpreted as a relative risk to the general population.

Objective: To compare the performance of GRS with two guideline-recommended inherited risk measures, family history (FH) and rare pathogenic mutations (RPMs), for predicting PCa incidence and mortality.

Design, Setting, And Participants: A prospective cohort was derived from the UK Biobank where 208 685 PCa diagnosis-free participants at recruitment were followed via the UK cancer and death registries.

Outcome Measurements And Statistical Analysis: Rate ratios (RRs) of PCa incidence and mortality for FH (positive vs negative), RPMs (carriers vs noncarriers), and GRS (top vs bottom quartile) were measured.

Results And Limitations: After a median follow-up of 9.67 yr, 6890 incident PCa cases (419 died of PCa) were identified. Each of the three measures was significantly associated with PCa incidence in univariate analyses; RR (95 % confidence interval [CI]) values were 1.88 (1.75-2.01) for FH, 2.89 (1.89-4.25) for RPMs, and 1.97(1.87-2.07) for GRS (all p < 0.001). The associations were independent in multivariable analyses. While FH and RPMs identified 11 % of men at higher PCa risk, addition of GRS identified an additional 22 % of men at higher PCa risk, and increases in C-statistic from 0.58 to 0.67 for differentiating incidence (p < 0.001) and from 0.65 to 0.71 for differentiating mortality (p = 0.002). Limitations were a small number of minority patients and short mortality follow-up.

Conclusions: This population-based prospective study suggests that GRS complements two guideline-recommended inherited risk measures (FH and RPMs) for stratifying the risk of PCa incidence and mortality.

Patient Summary: In a large population-based prostate cancer (PCa) prospective study derived from UK Biobank, genetic risk score (GRS) complements two guideline-recommended inherited risk measures (family history and rare pathogenic mutations) in predicting PCa incidence and mortality. These results provide critical data for including GRS in PCa risk assessment.
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http://dx.doi.org/10.1016/j.eururo.2020.11.014DOI Listing
March 2021

Associations between Plasma Choline Metabolites and Genetic Polymorphisms in One-Carbon Metabolism in Postmenopausal Women: The Women's Health Initiative Observational Study.

J Nutr 2020 11;150(11):2874-2881

Huntsman Cancer Institute, Salt Lake City, UT, USA.

Background: Choline plays an integral role in one-carbon metabolism in the body, but it is unclear whether genetic polymorphisms are associated with variations in plasma choline and its metabolites.

Objectives: This study aimed to evaluate the association of genetic variants in choline and one-carbon metabolism with plasma choline and its metabolites.

Methods: We analyzed data from 1423 postmenopausal women in a case-control study nested within the Women's Health Initiative Observational Study. Plasma concentrations of choline, betaine, dimethylglycine (DMG), and trimethylamine N-oxide were determined in 12-h fasting blood samples collected at baseline (1993-1998). Candidate and tagging single-nucleotide polymorphisms (SNPs) were genotyped in betaine-homocysteine S-methyltransferase (BHMT), BHMT2, 5,10-methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (NADP+ dependent 1) (MTHFD1), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR). Linear regression was used to derive percentage difference in plasma concentrations per variant allele, adjusting for confounders, including B-vitamin biomarkers. Potential effect modification by plasma vitamin B-12, vitamin B-6, and folate concentrations and folic-acid fortification periods was examined.

Results: The candidate SNP BHMT R239Q (rs3733890) was associated with lower concentrations of plasma betaine and DMG concentrations (-4.00% and -6.75% per variant allele, respectively; both nominal P < 0.05). Another candidate SNP, BHMT2 rs626105 A>G, was associated with higher plasma DMG concentration (13.0%; P < 0.0001). Several tagSNPs in these 2 genes were associated with plasma concentrations after correction for multiple comparisons. Vitamin B-12 status was a significant effect modifier of the association between the genetic variant BHMT2 rs626105 A>G and plasma DMG concentration.

Conclusions: Genetic variations in metabolic enzymes were associated with plasma concentrations of choline and its metabolites. Our findings contribute to the knowledge on the variation in blood nutrient concentrations in postmenopausal women.
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http://dx.doi.org/10.1093/jn/nxaa266DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7675024PMC
November 2020

Genome-wide Modeling of Polygenic Risk Score in Colorectal Cancer Risk.

Am J Hum Genet 2020 09 5;107(3):432-444. Epub 2020 Aug 5.

School of Public Health, Imperial College London, London SW7 2AZ, UK.

Accurate colorectal cancer (CRC) risk prediction models are critical for identifying individuals at low and high risk of developing CRC, as they can then be offered targeted screening and interventions to address their risks of developing disease (if they are in a high-risk group) and avoid unnecessary screening and interventions (if they are in a low-risk group). As it is likely that thousands of genetic variants contribute to CRC risk, it is clinically important to investigate whether these genetic variants can be used jointly for CRC risk prediction. In this paper, we derived and compared different approaches to generating predictive polygenic risk scores (PRS) from genome-wide association studies (GWASs) including 55,105 CRC-affected case subjects and 65,079 control subjects of European ancestry. We built the PRS in three ways, using (1) 140 previously identified and validated CRC loci; (2) SNP selection based on linkage disequilibrium (LD) clumping followed by machine-learning approaches; and (3) LDpred, a Bayesian approach for genome-wide risk prediction. We tested the PRS in an independent cohort of 101,987 individuals with 1,699 CRC-affected case subjects. The discriminatory accuracy, calculated by the age- and sex-adjusted area under the receiver operating characteristics curve (AUC), was highest for the LDpred-derived PRS (AUC = 0.654) including nearly 1.2 M genetic variants (the proportion of causal genetic variants for CRC assumed to be 0.003), whereas the PRS of the 140 known variants identified from GWASs had the lowest AUC (AUC = 0.629). Based on the LDpred-derived PRS, we are able to identify 30% of individuals without a family history as having risk for CRC similar to those with a family history of CRC, whereas the PRS based on known GWAS variants identified only top 10% as having a similar relative risk. About 90% of these individuals have no family history and would have been considered average risk under current screening guidelines, but might benefit from earlier screening. The developed PRS offers a way for risk-stratified CRC screening and other targeted interventions.
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http://dx.doi.org/10.1016/j.ajhg.2020.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7477007PMC
September 2020

Cumulative Burden of Colorectal Cancer-Associated Genetic Variants Is More Strongly Associated With Early-Onset vs Late-Onset Cancer.

Gastroenterology 2020 04 19;158(5):1274-1286.e12. Epub 2019 Dec 19.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington.

Background & Aims: Early-onset colorectal cancer (CRC, in persons younger than 50 years old) is increasing in incidence; yet, in the absence of a family history of CRC, this population lacks harmonized recommendations for prevention. We aimed to determine whether a polygenic risk score (PRS) developed from 95 CRC-associated common genetic risk variants was associated with risk for early-onset CRC.

Methods: We studied risk for CRC associated with a weighted PRS in 12,197 participants younger than 50 years old vs 95,865 participants 50 years or older. PRS was calculated based on single nucleotide polymorphisms associated with CRC in a large-scale genome-wide association study as of January 2019. Participants were pooled from 3 large consortia that provided clinical and genotyping data: the Colon Cancer Family Registry, the Colorectal Transdisciplinary Study, and the Genetics and Epidemiology of Colorectal Cancer Consortium and were all of genetically defined European descent. Findings were replicated in an independent cohort of 72,573 participants.

Results: Overall associations with CRC per standard deviation of PRS were significant for early-onset cancer, and were stronger compared with late-onset cancer (P for interaction = .01); when we compared the highest PRS quartile with the lowest, risk increased 3.7-fold for early-onset CRC (95% CI 3.28-4.24) vs 2.9-fold for late-onset CRC (95% CI 2.80-3.04). This association was strongest for participants without a first-degree family history of CRC (P for interaction = 5.61 × 10). When we compared the highest with the lowest quartiles in this group, risk increased 4.3-fold for early-onset CRC (95% CI 3.61-5.01) vs 2.9-fold for late-onset CRC (95% CI 2.70-3.00). Sensitivity analyses were consistent with these findings.

Conclusions: In an analysis of associations with CRC per standard deviation of PRS, we found the cumulative burden of CRC-associated common genetic variants to associate with early-onset cancer, and to be more strongly associated with early-onset than late-onset cancer, particularly in the absence of CRC family history. Analyses of PRS, along with environmental and lifestyle risk factors, might identify younger individuals who would benefit from preventive measures.
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http://dx.doi.org/10.1053/j.gastro.2019.12.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7103489PMC
April 2020

Broad- and narrow-sense validity performance of three polygenic risk score methods for prostate cancer risk assessment.

Prostate 2020 01 21;80(1):83-87. Epub 2019 Oct 21.

Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, Illinois.

Background: Several polygenic risk score (PRS) methods are available for measuring the cumulative effect of multiple risk-associated single nucleotide polymorphisms (SNPs). Their performance in predicting risk at the individual level has not been well studied.

Methods: We compared the performance of three PRS methods for prostate cancer risk assessment in a clinical trial cohort, including genetic risk score (GRS), pruning and thresholding (P + T), and linkage disequilibrium prediction (LDpred). Performance was evaluated for score deciles (broad-sense validity) and score values (narrow-sense validity).

Results: A training process was required to identify the best P + T model (397 SNPs) and LDpred model (3 011 362 SNPs). In contrast, GRS was directly calculated based on 110 established risk-associated SNPs. For broad-sense validity in the testing population, higher deciles were significantly associated with higher observed risk; P was 7.40 × 10 , 7.64 × 10 , and 7.51 × 10 for GRS, P + T, and LDpred, respectively. For narrow-sense validity, the calibration slope (1 is best) was 1.03, 0.77, and 0.87, and mean bias score (0 is best) was 0.09, 0.21, and 0.10 for GRS, P + T, and LDpred, respectively.

Conclusions: The performance of GRS was better than P + T and LDpred. Fewer and well-established SNPs of GRS also make it more feasible and interpretable for genetic testing at the individual level.
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http://dx.doi.org/10.1002/pros.23920DOI Listing
January 2020

Association of a Pathway-Specific Genetic Risk Score With Risk of Radiation-Associated Contralateral Breast Cancer.

JAMA Netw Open 2019 09 4;2(9):e1912259. Epub 2019 Sep 4.

Memorial Sloan Kettering Cancer Center, New York, New York.

Importance: Radiation therapy for breast cancer is associated with increased risk of a second primary contralateral breast cancer, but the genetic factors modifying this association are not well understood.

Objective: To determine whether a genetic risk score comprising single nucleotide polymorphisms in the nonhomologous end-joining DNA repair pathway is associated with radiation-associated contralateral breast cancer.

Design, Setting, And Participants: This case-control study included a case group of women with contralateral breast cancer that was diagnosed at least 1 year after a first primary breast cancer who were individually matched to a control group of women with unilateral breast cancer. Inclusion criteria were receiving a first invasive breast cancer diagnosis prior to age 55 years between 1985 and 2008. Women were recruited through 8 population-based cancer registries in the United States, Canada, and Denmark as part of the Women's Environment, Cancer, and Radiation Epidemiology Studies I (November 2000 to August 2004) and II (March 2010 to December 2012). Data analysis was conducted from July 2017 to August 2019.

Exposures: Stray radiation dose to the contralateral breast during radiation therapy for the first breast cancer. A novel genetic risk score comprised of genetic variants in the nonhomologous end-joining DNA repair pathway was considered the potential effect modifier, dichotomized as high risk if the score was above the median of 74 and low risk if the score was at or below the median.

Main Outcomes And Measures: The main outcome was risk of contralateral breast cancer associated with stray radiation dose stratified by genetic risk score, age, and latency.

Results: A total of 5953 women were approached for study participation, and 3732 women (62.7%) agreed to participate. The median (range) age at first diagnosis was 46 (23-54) years. After 5 years of latency or more, among women who received the first diagnosis when they were younger than 40 years, exposure to 1.0 Gy (to convert to rad, multiply by 100) or more of stray radiation was associated with a 2-fold increased risk of contralateral breast cancer compared with women who were not exposed (rate ratio, 2.0 [95% CI, 1.1-3.6]). The risk was higher among women with a genetic risk score above the median (rate ratio, 3.0 [95% CI, 1.1-8.1]), and there was no association among women with a genetic risk score below the median (rate ratio, 1.3 [95% CI, 0.5-3.7]). Among younger women with a high genetic risk score, the attributable increased risk for contralateral breast cancer associated with stray radiation dose was 28%.

Conclusions And Relevance: This study found an increased risk of contralateral breast cancer that was attributable to stray radiation exposure among women with a high genetic risk score and who received a first breast cancer diagnosis when they were younger than 40 years after 5 years or more of latency. This genetic risk score may help guide treatment and surveillance for women with breast cancer.
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http://dx.doi.org/10.1001/jamanetworkopen.2019.12259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777239PMC
September 2019

Ability of known susceptibility SNPs to predict colorectal cancer risk for persons with and without a family history.

Fam Cancer 2019 10;18(4):389-397

Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, VIC, 3010, Australia.

Before SNP-based risk can be incorporated in colorectal cancer (CRC) screening, the ability of these SNPs to estimate CRC risk for persons with and without a family history of CRC, and the screening implications need to be determined. We estimated the association with CRC of a 45 SNP-based risk using 1181 cases and 999 controls, and its correlation with CRC risk predicted from detailed family history. We estimated the predicted change in the distribution across predefined risk categories, and implications for recommended screening commencement age, from adding SNP-based risk to family history. The inter-quintile risk ratio for colorectal cancer risk of the SNP-based risk was 3.28 (95% CI 2.54-4.22). SNP-based and family history-based risks were not correlated (r = 0.02). For persons with no first-degree relatives with CRC, screening could commence 4 years earlier for women (5 years for men) in the highest quintile of SNP-based risk. For persons with two first-degree relatives with CRC, screening could commence 16 years earlier for men and women in the highest quintile, and 7 years earlier for the lowest quintile. This 45 SNP panel in conjunction with family history, can identify people who could benefit from earlier screening. Risk reclassification by 45 SNPs could inform targeted screening for CRC prevention, particularly in clinical genetics settings when mutations in high-risk genes cannot be identified. Yet to be determined is cost-effectiveness, resources requirements, community, patient and clinician acceptance, and feasibility with potentially ethical, legal and insurance implications.
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http://dx.doi.org/10.1007/s10689-019-00136-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6785388PMC
October 2019

Association analyses identify 31 new risk loci for colorectal cancer susceptibility.

Nat Commun 2019 05 14;10(1):2154. Epub 2019 May 14.

Wellcome Centre for Human Genetics, McCarthy Group, Roosevelt Drive, Oxford, OX3 7BN, UK.

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide, and has a strong heritable basis. We report a genome-wide association analysis of 34,627 CRC cases and 71,379 controls of European ancestry that identifies SNPs at 31 new CRC risk loci. We also identify eight independent risk SNPs at the new and previously reported European CRC loci, and a further nine CRC SNPs at loci previously only identified in Asian populations. We use in situ promoter capture Hi-C (CHi-C), gene expression, and in silico annotation methods to identify likely target genes of CRC SNPs. Whilst these new SNP associations implicate target genes that are enriched for known CRC pathways such as Wnt and BMP, they also highlight novel pathways with no prior links to colorectal tumourigenesis. These findings provide further insight into CRC susceptibility and enhance the prospects of applying genetic risk scores to personalised screening and prevention.
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http://dx.doi.org/10.1038/s41467-019-09775-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6517433PMC
May 2019

Concept and benchmarks for assessing narrow-sense validity of genetic risk score values.

Prostate 2019 07 29;79(10):1099-1105. Epub 2019 Apr 29.

Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, Illinois.

Background: While higher genetic risk score (GRS) has been statistically associated with increased disease risk (broad-sense validity), the concept and tools for assessing the validity of reported GRS values from tests (narrow-sense validity) are underdeveloped.

Methods: We propose two benchmarks for assessing the narrow-sense validity of GRS. The baseline benchmark requires that the mean GRS value in a general population approximates 1.0. The calibration benchmark assesses the agreement between observed risks and estimated risks (GRS values). We assessed benchmark performance for three prostate cancer (PCa) GRS tests, derived from three SNP panels with increasing stringency of selection criteria, in a PCa chemoprevention trial where 714 of 3225 men were diagnosed with PCa during the 4-year follow-up.

Results: GRS from Panels 1, 2, and 3 were all statistically associated with PCa risk; P = 5.58 × 10 , P = 1 × 10 , and P = 1.5 × 10 , respectively (broad-sense validity). For narrow-sense validity, the mean GRS value among men without PCa was 1.33, 1.09, and 0.98 for Panels 1, 2, and 3, respectively (baseline benchmark). For assessing the calibration benchmark, observed risks were calculated for seven groups of men with GRS values <0.3, 0.3-0.79, 0.8-1.19, 1.2-1.49, 1.5-1.99, 2-2.99, and ≥3. The calibration slope (higher is better) was 0.15, 0.12, and 0.60, and the bias score (lower is better) between the observed risks and GRS values was 0.08, 0.08, and 0.02 for Panels 1, 2, and 3, respectively.

Conclusion: Performance differed considerably among GRS tests. We recommend that all GRS tests be evaluated using the two benchmarks before clinical implementation for individual risk assessment.
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http://dx.doi.org/10.1002/pros.23821DOI Listing
July 2019

Systematic evaluation of cancer-specific genetic risk score for 11 types of cancer in The Cancer Genome Atlas and Electronic Medical Records and Genomics cohorts.

Cancer Med 2019 06 9;8(6):3196-3205. Epub 2019 Apr 9.

Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, Illinois.

Background: Genetic risk score (GRS) is an odds ratio (OR)-weighted and population-standardized method for measuring cumulative effect of multiple risk-associated single nucleotide polymorphisms (SNPs). We hypothesize that GRS is a valid tool for risk assessment of most common cancers.

Methods: Utilizing genotype and phenotype data from The Cancer Genome Atlas (TCGA) and Electronic Medical Records and Genomics (eMERGE), we tested 11 cancer-specific GRSs (bladder, breast, colorectal, glioma, lung, melanoma, ovarian, pancreatic, prostate, renal, and thyroid cancer) for association with the respective cancer type. Cancer-specific GRSs were calculated, for the first time in these cohorts, based on previously published risk-associated SNPs using the Caucasian subjects in these two cohorts.

Results: Mean cancer-specific GRS in the population controls of eMERGE approximated the expected value of 1.00 (between 0.98 and 1.02) for all 11 types of cancer. Mean cancer-specific GRS was consistently higher in respective cancer patients than controls for all 11 types of cancer (P < 0.05). When subjects were categorized into low-, average-, and high-risk groups based on cancer-specific GRS (<0.5, 0.5-1.5, and >1.5, respectively), significant dose-response associations of higher cancer-specific GRS with higher OR of respective type of cancer were found for nine types of cancer (P  < 0.05). More than 64% subjects in the population controls of eMERGE can be classified as high risk for at least one type of these cancers.

Conclusion: Validity of GRS for predicting cancer risk is demonstrated for most types of cancer. If confirmed in larger studies, cancer-specific GRS may have the potential for developing personalized cancer screening strategy.
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http://dx.doi.org/10.1002/cam4.2143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558466PMC
June 2019

Discovery of common and rare genetic risk variants for colorectal cancer.

Nat Genet 2019 01 3;51(1):76-87. Epub 2018 Dec 3.

Department of Epidemiology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Germany.

To further dissect the genetic architecture of colorectal cancer (CRC), we performed whole-genome sequencing of 1,439 cases and 720 controls, imputed discovered sequence variants and Haplotype Reference Consortium panel variants into genome-wide association study data, and tested for association in 34,869 cases and 29,051 controls. Findings were followed up in an additional 23,262 cases and 38,296 controls. We discovered a strongly protective 0.3% frequency variant signal at CHD1. In a combined meta-analysis of 125,478 individuals, we identified 40 new independent signals at P < 5 × 10, bringing the number of known independent signals for CRC to ~100. New signals implicate lower-frequency variants, Krüppel-like factors, Hedgehog signaling, Hippo-YAP signaling, long noncoding RNAs and somatic drivers, and support a role for immune function. Heritability analyses suggest that CRC risk is highly polygenic, and larger, more comprehensive studies enabling rare variant analysis will improve understanding of biology underlying this risk and influence personalized screening strategies and drug development.
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http://dx.doi.org/10.1038/s41588-018-0286-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6358437PMC
January 2019

Novel Common Genetic Susceptibility Loci for Colorectal Cancer.

J Natl Cancer Inst 2019 02;111(2):146-157

Division of Research, Kaiser Permanente Medical Care Program of Northern California, Oakland, CA.

Background: Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10-8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk.

Methods: We conducted a GWAS in European descent CRC cases and control subjects using a discovery-replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10-8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided.

Results: The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10-8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0.

Conclusions: This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.
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http://dx.doi.org/10.1093/jnci/djy099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555904PMC
February 2019

Breast Cancer Family History and Contralateral Breast Cancer Risk in Young Women: An Update From the Women's Environmental Cancer and Radiation Epidemiology Study.

J Clin Oncol 2018 05 5;36(15):1513-1520. Epub 2018 Apr 5.

Anne S. Reiner, Julia Sisti, Marinela Capanu, Mark Robson, Xiaolin Liang, Meghan Woods, and Jonine L. Bernstein, Memorial Sloan Kettering Cancer Center; Mark Robson, Cornell University; Roy Shore, New York University School of Medicine, New York, NY; Esther M. John, Cancer Prevention Institute of California, Fremont, and Stanford School of Medicine, Stanford; David V. Conti, Daniel O. Stram, and Duncan C. Thomas, University of Southern California, Los Angeles; Leslie Bernstein, City of Hope National Medical Center, Duarte, CA; Charles F. Lynch, University of Iowa, Iowa City, IA; Jennifer D. Brooks and Julia A. Knight, University of Toronto; Julia A. Knight, Sinai Health System, Toronto, Ontario, Canada; Lene Mellemkjær, Danish Cancer Society Research Center, Copenhagen, Denmark; John D. Boice, Vanderbilt University Medical Center and the Vanderbilt-Ingram Cancer Center, Nashville, TN; Patrick Concannon, University of Florida, Gainesville, FL; Marc Tischkowitz, University of Cambridge, Cambridge, United Kingdom; David Duggan, Translational Genomics Research Institute, Phoenix, AZ; and Kathleen E. Malone, Fred Hutchinson Cancer Research Center, Seattle, WA.

Purpose The Women's Environmental Cancer and Radiation Epidemiology (WECARE) study demonstrated the importance of breast cancer family history on contralateral breast cancer (CBC) risk, even for noncarriers of deleterious BRCA1/2 mutations. With the completion of WECARE II, updated risk estimates are reported. Additional analyses that exclude women negative for deleterious mutations in ATM, CHEK2*1100delC, and PALB2 were performed. Patients and Methods The WECARE Study is a population-based case-control study that compared 1,521 CBC cases with 2,212 individually matched unilateral breast cancer (UBC) controls. Participants were younger than age 55 years when diagnosed with a first invasive breast cancer between 1985 and 2008. Women were interviewed about breast cancer risk factors, including family history. A subset of women was screened for deleterious mutations in BRCA1/2, ATM, CHEK2*1100delC, and PALB2. Rate ratios (RRs) were estimated using multivariable conditional logistic regression. Cumulative absolute risks (ARs) were estimated by combining RRs from the WECARE Study and population-based SEER*Stat cancer incidence data. Results Women with any first-degree relative with breast cancer had a 10-year AR of 8.1% for CBC (95% CI, 6.7% to 9.8%). Risks also were increased if the relative was diagnosed at an age younger than 40 years (10-year AR, 13.5%; 95% CI, 8.8% to 20.8%) or with CBC (10-year AR, 14.1%; 95% CI, 9.5% to 20.7%). These risks are comparable with those seen in BRCA1/2 deleterious mutation carriers (10-year AR, 18.4%; 95% CI, 16.0% to 21.3%). In the subset of women who tested negative for deleterious mutations in BRCA1/2, ATM, CHEK2*1100delC, and PALB2, estimates were unchanged. Adjustment for known breast cancer single-nucleotide polymorphisms did not affect estimates. Conclusion Breast cancer family history confers a high CBC risk, even after excluding women with deleterious mutations. Clinicians are urged to use detailed family histories to guide treatment and future screening decisions for young women with breast cancer.
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http://dx.doi.org/10.1200/JCO.2017.77.3424DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5959199PMC
May 2018

Genetic Determinants of Radiographic Knee Osteoarthritis in African Americans.

J Rheumatol 2017 Nov 15;44(11):1652-1658. Epub 2017 Sep 15.

From the Thurston Arthritis Research Center, and the Department of Radiology, and the Departments of Medicine and Orthopaedics, University of North Carolina, Chapel Hill, North Carolina; Departments of Medicine and Epidemiology and Public Health, University of Maryland School of Medicine; Medical Care Clinical Center, Veterans Affairs Maryland Health Care System; Geriatric Research, Education and Clinical Center, Veterans Affairs Medical Center, Baltimore, Maryland; Institute for Aging Research, Hebrew SeniorLife; Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts; Translational Genomics Research Institute, Phoenix, Arizona; Department of Internal Medicine, Ohio State University, Columbus, Ohio, USA.

Objective: The etiology of knee osteoarthritis (OA), the most common form of arthritis, is complex and may differ by race or ethnicity. In recent years, genetic studies have identified many genetic variants associated with OA, but nearly all the studies were conducted in European whites and Asian Americans. Few studies have focused on the genetics of knee OA in African Americans.

Methods: We performed a genome-wide association study of radiographic knee OA in 1217 African Americans from 2 North American cohort studies: 590 subjects from the Johnston County Osteoarthritis Project and 627 subjects from the Osteoarthritis Initiative. Analyses were conducted in each cohort separately and combined in an inverse variance fixed effects metaanalysis, which were then included in pathway analyses. We additionally tested 12 single-nucleotide polymorphisms robustly associated with OA in European white populations for association in African Americans.

Results: We identified a genome-wide significant variant in (minor allele frequency 12%; p = 4.11 × 10) that is less common in European white populations (minor allele frequency < 3%). Five other independent loci reached suggestive significance (p < 1 × 10). In pathway analyses, dorsal/ventral neural tube patterning and iron ion transport pathways were significantly associated with knee OA in African Americans (false discovery rate < 0.05). We found no evidence that previously reported OA susceptibility variants in European whites were associated with knee OA in African Americans.

Conclusion: These results highlight differences in the genetic architecture of knee OA between African American and European whites. This finding underscores the need to include more diverse populations in OA genetics studies.
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http://dx.doi.org/10.3899/jrheum.161488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5668168PMC
November 2017

Association of Common Genetic Variants With Contralateral Breast Cancer Risk in the WECARE Study.

J Natl Cancer Inst 2017 10;109(10)

Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York,NY, USA.

Background: Women with unilateral breast cancer (UBC) are at risk of developing a subsequent contralateral breast cancer (CBC). Common variants are associated with breast cancer risk. Whether these influence CBC risk is unknown.

Methods: Participants were breast cancer cases from the population-based Women's Environmental Cancer and Radiation Epidemiology (WECARE) Study. Sixty-seven established breast cancer risk loci were genotyped directly or by imputation in 1459 case subjects with CBC and 2126 UBC control subjects. An unweighted polygenic risk score (PRS) was created by summing the number of risk alleles for each directly genotyped single nucleotide polymorphism (SNP), or for imputed loci, the imputed dosage. A weighted PRS was calculated similarly, but where each SNP's contribution was weighted by the published per-allele log odds ratio. Unweighted and weighted polygenic risk scores and CBC risk were modeled using conditional logistic regression. Cumulative CBC risk was estimated and benchmarked using Surveillance, Epidemiology, and End Results population incidence rates.

Results: Both unweighted and weighted PRS were statistically significantly associated with CBC risk. The adjusted risk ratio of CBC in women in the upper quartile of unweighted PRS compared with the lowest quartile was 1.63 (95% confidence interval [CI] = 1.33 to 2.00). The estimated 10-year cumulative risk for women in the upper quartile of the unweighted PRS was 7.4% (95% CI = 6.0% to 9.1%). For women in the upper quartile of the weighted PRS, the risk ratio for CBC was 1.75 (95% CI = 1.41 to 2.18) compared with women in the lowest quartile. There was no statistically significant heterogeneity by age, treatment (radiation therapy dose, tamoxifen, chemotherapy), estrogen receptor status of the first primary, histology of the first primary, length of at-risk period for CBC, or breast cancer family history.

Conclusions: Common genomic variants associated with the development of first primary breast cancer are also associated with the development of CBC; the risk is strongest among those who carry more risk alleles.
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http://dx.doi.org/10.1093/jnci/djx051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5939625PMC
October 2017

Genome-Wide Interaction Analyses between Genetic Variants and Alcohol Consumption and Smoking for Risk of Colorectal Cancer.

PLoS Genet 2016 Oct 10;12(10):e1006296. Epub 2016 Oct 10.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.

Genome-wide association studies (GWAS) have identified many genetic susceptibility loci for colorectal cancer (CRC). However, variants in these loci explain only a small proportion of familial aggregation, and there are likely additional variants that are associated with CRC susceptibility. Genome-wide studies of gene-environment interactions may identify variants that are not detected in GWAS of marginal gene effects. To study this, we conducted a genome-wide analysis for interaction between genetic variants and alcohol consumption and cigarette smoking using data from the Colon Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Interactions were tested using logistic regression. We identified interaction between CRC risk and alcohol consumption and variants in the 9q22.32/HIATL1 (Pinteraction = 1.76×10-8; permuted p-value 3.51x10-8) region. Compared to non-/occasional drinking light to moderate alcohol consumption was associated with a lower risk of colorectal cancer among individuals with rs9409565 CT genotype (OR, 0.82 [95% CI, 0.74-0.91]; P = 2.1×10-4) and TT genotypes (OR,0.62 [95% CI, 0.51-0.75]; P = 1.3×10-6) but not associated among those with the CC genotype (p = 0.059). No genome-wide statistically significant interactions were observed for smoking. If replicated our suggestive finding of a genome-wide significant interaction between genetic variants and alcohol consumption might contribute to understanding colorectal cancer etiology and identifying subpopulations with differential susceptibility to the effect of alcohol on CRC risk.
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http://dx.doi.org/10.1371/journal.pgen.1006296DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5065124PMC
October 2016

Genome-Wide Association Study of Radiographic Knee Osteoarthritis in North American Caucasians.

Arthritis Rheumatol 2017 02;69(2):343-351

The Ohio State University, Columbus.

Objective: A major barrier to genetic studies of osteoarthritis (OA) is the need to obtain large numbers of individuals with standardized radiographic evaluations for OA. To address this gap, we performed a genome-wide association study (GWAS) of radiographically defined tibiofemoral knee OA in 3,898 cases and 3,168 controls from 4 well-characterized North American cohorts, and we performed replication analysis of previously reported OA loci.

Methods: We performed meta-analysis using a 2-stage design. Stage 1 (discovery) consisted of a GWAS meta-analysis of radiographic knee OA carried out in the Osteoarthritis Initiative and the Johnston County Osteoarthritis Project. Knee OA was defined as definite osteophytes and possible joint space narrowing or total joint replacement in one or both knees. Stage 2 (validation) was performed in the Multicenter Osteoarthritis Study and the Genetics of Osteoarthritis study. We genotyped lead meta-analysis variants (P ≤ 1 × 10 ) from stage 1 and tested the association between these variants and knee OA. We then combined results from all cohorts in a meta-analysis.

Results: Lead variants from stage 1, representing 49 unique loci, were analyzed in stage 2; none met genome-wide significance in the combined analysis of stage 1 and stage 2. We validated 1 locus (rs4867568 near LSP1P3) with nominal significance (P < 0.05), which was also our top finding in the combined meta-analysis (odds ratio [OR] 0.84 [95% confidence interval (95% CI) 0.79-0.91], P = 3.02 × 10 ). We observed nominally significant associations (P < 0.05) with 3 previously reported OA loci: rs143383 in GDF5 (OR 1.12 [95% CI 1.04-1.21], P = 2.13 × 10 ), rs835487 in CHST11 (OR 0.93 [95% CI 0.85-0.99], P = 0.03), and rs8044769 in FTO (OR 1.10 [95% CI 1.03-1.19], P = 6.13 × 10 ).

Conclusion: These findings provide suggestive evidence of a novel knee OA locus and confirm previously reported associations in GDF5, CHST11, and FTO.
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http://dx.doi.org/10.1002/art.39932DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5274579PMC
February 2017

Fine-Mapping of Common Genetic Variants Associated with Colorectal Tumor Risk Identified Potential Functional Variants.

PLoS One 2016 5;11(7):e0157521. Epub 2016 Jul 5.

Department of Medicine and Epidemiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America.

Genome-wide association studies (GWAS) have identified many common single nucleotide polymorphisms (SNPs) associated with colorectal cancer risk. These SNPs may tag correlated variants with biological importance. Fine-mapping around GWAS loci can facilitate detection of functional candidates and additional independent risk variants. We analyzed 11,900 cases and 14,311 controls in the Genetics and Epidemiology of Colorectal Cancer Consortium and the Colon Cancer Family Registry. To fine-map genomic regions containing all known common risk variants, we imputed high-density genetic data from the 1000 Genomes Project. We tested single-variant associations with colorectal tumor risk for all variants spanning genomic regions 250-kb upstream or downstream of 31 GWAS-identified SNPs (index SNPs). We queried the University of California, Santa Cruz Genome Browser to examine evidence for biological function. Index SNPs did not show the strongest association signals with colorectal tumor risk in their respective genomic regions. Bioinformatics analysis of SNPs showing smaller P-values in each region revealed 21 functional candidates in 12 loci (5q31.1, 8q24, 11q13.4, 11q23, 12p13.32, 12q24.21, 14q22.2, 15q13, 18q21, 19q13.1, 20p12.3, and 20q13.33). We did not observe evidence of additional independent association signals in GWAS-identified regions. Our results support the utility of integrating data from comprehensive fine-mapping with expanding publicly available genomic databases to help clarify GWAS associations and identify functional candidates that warrant more onerous laboratory follow-up. Such efforts may aid the eventual discovery of disease-causing variant(s).
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0157521PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933364PMC
July 2017

GWASeq: targeted re-sequencing follow up to GWAS.

BMC Genomics 2016 Mar 3;17:176. Epub 2016 Mar 3.

Department of Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.

Background: For the last decade the conceptual framework of the Genome-Wide Association Study (GWAS) has dominated the investigation of human disease and other complex traits. While GWAS have been successful in identifying a large number of variants associated with various phenotypes, the overall amount of heritability explained by these variants remains small. This raises the question of how best to follow up on a GWAS, localize causal variants accounting for GWAS hits, and as a consequence explain more of the so-called "missing" heritability. Advances in high throughput sequencing technologies now allow for the efficient and cost-effective collection of vast amounts of fine-scale genomic data to complement GWAS.

Results: We investigate these issues using a colon cancer dataset. After QC, our data consisted of 1993 cases, 899 controls. Using marginal tests of associations, we identify 10 variants distributed among six targeted regions that are significantly associated with colorectal cancer, with eight of the variants being novel to this study. Additionally, we perform so-called 'SNP-set' tests of association and identify two sets of variants that implicate both common and rare variants in the etiology of colorectal cancer.

Conclusions: Here we present a large-scale targeted re-sequencing resource focusing on genomic regions implicated in colorectal cancer susceptibility previously identified in several GWAS, which aims to 1) provide fine-scale targeted sequencing data for fine-mapping and 2) provide data resources to address methodological questions regarding the design of sequencing-based follow-up studies to GWAS. Additionally, we show that this strategy successfully identifies novel variants associated with colorectal cancer susceptibility and can implicate both common and rare variants.
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http://dx.doi.org/10.1186/s12864-016-2459-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776370PMC
March 2016

CYP24A1 variant modifies the association between use of oestrogen plus progestogen therapy and colorectal cancer risk.

Br J Cancer 2016 Jan 14;114(2):221-9. Epub 2016 Jan 14.

Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA.

Background: Menopausal hormone therapy (MHT) use has been consistently associated with a decreased risk of colorectal cancer (CRC) in women. Our aim was to use a genome-wide gene-environment interaction analysis to identify genetic modifiers of CRC risk associated with use of MHT.

Methods: We included 10 835 postmenopausal women (5419 cases and 5416 controls) from 10 studies. We evaluated use of any MHT, oestrogen-only (E-only) and combined oestrogen-progestogen (E+P) hormone preparations. To test for multiplicative interactions, we applied the empirical Bayes (EB) test as well as the Wald test in conventional case-control logistic regression as primary tests. The Cocktail test was used as secondary test.

Results: The EB test identified a significant interaction between rs964293 at 20q13.2/CYP24A1 and E+P (interaction OR (95% CIs)=0.61 (0.52-0.72), P=4.8 × 10(-9)). The secondary analysis also identified this interaction (Cocktail test OR=0.64 (0.52-0.78), P=1.2 × 10(-5) (alpha threshold=3.1 × 10(-4)). The ORs for association between E+P and CRC risk by rs964293 genotype were as follows: C/C, 0.96 (0.61-1.50); A/C, 0.61 (0.39-0.95) and A/A, 0.40 (0.22-0.73), respectively.

Conclusions: Our results indicate that rs964293 modifies the association between E+P and CRC risk. The variant is located near CYP24A1, which encodes an enzyme involved in vitamin D metabolism. This novel finding offers additional insight into downstream pathways of CRC etiopathogenesis.
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http://dx.doi.org/10.1038/bjc.2015.443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4815813PMC
January 2016

Common genetic variation and survival after colorectal cancer diagnosis: a genome-wide analysis.

Carcinogenesis 2016 Jan 19;37(1):87-95. Epub 2015 Nov 19.

Division of Cancer Control and Population Sciences , National Cancer Institute , National Institutes of Health , Bethesda , MD 20892 , USA , and.

Genome-wide association studies have identified several germline single nucleotide polymorphisms (SNPs) significantly associated with colorectal cancer (CRC) incidence. Common germline genetic variation may also be related to CRC survival. We used a discovery-based approach to identify SNPs related to survival outcomes after CRC diagnosis. Genome-wide genotyping arrays were conducted for 3494 individuals with invasive CRC enrolled in six prospective cohort studies (median study-specific follow-up = 4.2-8.1 years). In pooled analyses, we used Cox regression to assess SNP-specific associations with CRC-specific and overall survival, with additional analyses stratified by stage at diagnosis. Top findings were followed-up in independent studies. A P value threshold of P < 5×10(-8) in analyses combining discovery and follow-up studies was required for genome-wide significance. Among individuals with distant-metastatic CRC, several SNPs at 6p12.1, nearest the ELOVL5 gene, were statistically significantly associated with poorer survival, with the strongest associations noted for rs209489 [hazard ratio (HR) = 1.8, P = 7.6×10(-10) and HR = 1.8, P = 3.7×10(-9) for CRC-specific and overall survival, respectively). No SNPs were statistically significantly associated with survival among all cases combined or in cases without distant-metastases. SNPs in 6p12.1/ELOVL5 were associated with survival outcomes in individuals with distant-metastatic CRC, and merit further follow-up for functional significance. Findings from this genome-wide association study highlight the potential importance of genetic variation in CRC prognosis and provide clues to genomic regions of potential interest.
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http://dx.doi.org/10.1093/carcin/bgv161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4715234PMC
January 2016

Genome-wide association study of colorectal cancer identifies six new susceptibility loci.

Nat Commun 2015 Jul 7;6:7138. Epub 2015 Jul 7.

Harvard Medical School, Boston, Massachusetts 02114, USA.

Genetic susceptibility to colorectal cancer is caused by rare pathogenic mutations and common genetic variants that contribute to familial risk. Here we report the results of a two-stage association study with 18,299 cases of colorectal cancer and 19,656 controls, with follow-up of the most statistically significant genetic loci in 4,725 cases and 9,969 controls from two Asian consortia. We describe six new susceptibility loci reaching a genome-wide threshold of P<5.0E-08. These findings provide additional insight into the underlying biological mechanisms of colorectal cancer and demonstrate the scientific value of large consortia-based genetic epidemiology studies.
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http://dx.doi.org/10.1038/ncomms8138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4967357PMC
July 2015

Folate-mediated one-carbon metabolism genes and interactions with nutritional factors on colorectal cancer risk: Women's Health Initiative Observational Study.

Cancer 2015 Oct 24;121(20):3684-91. Epub 2015 Jun 24.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.

Background: Investigations of folate-mediated one-carbon metabolism (FOCM) genes and gene-nutrient interactions with respect to colorectal cancer (CRC) risk are limited to candidate polymorphisms and dietary folate. This study comprehensively investigated associations between genetic variants in FOCM and CRC risk and whether the FOCM nutrient status modified these associations.

Methods: Two hundred eighty-eight candidate and tagging single-nucleotide polymorphisms (SNPs) in 30 FOCM genes were genotyped for 821 incident CRC case-control matched pairs in the Women's Health Initiative Observational Study cohort. FOCM biomarkers (red blood cell [RBC] folate, plasma folate, pyridoxal-5'-phosphate [PLP], vitamin B12, and homocysteine) and self-reported alcohol consumption were measured at the baseline. Conditional logistic regression was implemented; effect modification was examined on the basis of known enzyme-nutrient relations.

Results: Statistically significant associations were observed between CRC risk and functionally defined candidate SNPs of methylenetetrahydrofolate dehydrogenase 1 (MTHFD1; K134R), 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR; P450R), and PR domain containing 2 with ZNF domain (PRDM2; S450N) and a literature candidate SNP of thymidylate synthase (TYMS; g.676789A>T; nominal P < .05). In addition, suggestive associations were noted for tagging SNPs in cystathionine-β-synthase (CBS), dihydrofolate reductase (DHFR), DNA (cytosine-5-)-methyltransferase 3β (DNMT3B), methionine adenosyltransferase I α (MAT1A), MTHFD1, and MTRR (nominal P < .05; adjusted P, not significant). Significant interactions between nutrient biomarkers and candidate polymorphisms were observed for 1) plasma/RBC folate and folate hydrolase 1 (FOLH1), paraoxonase 1 (PON1), transcobalamin II (TCN2), DNMT1, and DNMT3B; 2) plasma PLP and TYMS TS3; 3) plasma B12 and betaine-homocysteine S-methyltransferase 2 (BHMT2); and 4) homocysteine and methylenetetrahydrofolate reductase (MTHFR) and alanyl-transfer RNA synthetase (AARS).

Conclusions: Genetic variants in FOCM genes are associated with CRC risk among postmenopausal women. FOCM nutrients continue to emerge as effect modifiers of genetic influences on CRC risk.
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http://dx.doi.org/10.1002/cncr.29465DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592375PMC
October 2015

Identification of a common variant with potential pleiotropic effect on risk of inflammatory bowel disease and colorectal cancer.

Carcinogenesis 2015 Sep 12;36(9):999-1007. Epub 2015 Jun 12.

Division of Epidemiology, New York University School of Medicine, New York, NY, USA.

Although genome-wide association studies (GWAS) have separately identified many genetic susceptibility loci for ulcerative colitis (UC), Crohn's disease (CD) and colorectal cancer (CRC), there has been no large-scale examination for pleiotropy, or shared genetic susceptibility, for these conditions. We used logistic regression modeling to examine the associations of 181 UC and CD susceptibility variants previously identified by GWAS with risk of CRC using data from the Genetics and Epidemiology of Colorectal Cancer Consortium and the Colon Cancer Family Registry. We also examined associations of significant variants with clinical and molecular characteristics in a subset of the studies. Among 11794 CRC cases and 14190 controls, rs11676348, the susceptibility single nucleotide polymorphism (SNP) for UC, was significantly associated with reduced risk of CRC (P = 7E-05). The multivariate-adjusted odds ratio of CRC with each copy of the T allele was 0.93 (95% CI 0.89-0.96). The association of the SNP with risk of CRC differed according to mucinous histological features (P heterogeneity = 0.008). In addition, the (T) allele was associated with lower risk of tumors with Crohn's-like reaction but not tumors without such immune infiltrate (P heterogeneity = 0.02) and microsatellite instability-high (MSI-high) but not microsatellite stable or MSI-low tumors (P heterogeneity = 0.03). The minor allele (T) in SNP rs11676348, located downstream from CXCR2 that has been implicated in CRC progression, is associated with a lower risk of CRC, particularly tumors with a mucinous component, Crohn's-like reaction and MSI-high. Our findings offer the promise of risk stratification of inflammatory bowel disease patients for complications such as CRC.
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http://dx.doi.org/10.1093/carcin/bgv086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573660PMC
September 2015

Mendelian randomization study of height and risk of colorectal cancer.

Int J Epidemiol 2015 Apr 20;44(2):662-72. Epub 2015 May 20.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA, Department of Medicine and Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA, Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA, Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, UT, USA, Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA, Estonian Genome Center, University of Tartu, Tartu, Estonia, Divisions of Endocrinology and Genetics and Center for Basic Translational Obesity Research, Boston Children's Hospital, Boston, MA, USA, Department of Genetics, Harvard Medical School, Boston, MA, USA, Broad Institute, Cambridge, MA, USA, Genetics of Complex Traits, University of Exeter Medical School, Exeter, UK, Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia, University of Queensland Diamantina Institute, Translation Research Institute, Brisbane, QLD, Australia, Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark, Department of Medical Sciences, Uppsala University, Uppsala, Sweden, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC, USA, CHU Nantes, Service de Génétique Médicale, Nantes, France, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA, Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA, USC Norris

Background: For men and women, taller height is associated with increased risk of all cancers combined. For colorectal cancer (CRC), it is unclear whether the differential association of height by sex is real or is due to confounding or bias inherent in observational studies. We performed a Mendelian randomization study to examine the association between height and CRC risk.

Methods: To minimize confounding and bias, we derived a weighted genetic risk score predicting height (using 696 genetic variants associated with height) in 10,226 CRC cases and 10,286 controls. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for associations between height, genetically predicted height and CRC.

Results: Using conventional methods, increased height (per 10-cm increment) was associated with increased CRC risk (OR = 1.08, 95% CI = 1.02-1.15). In sex-specific analyses, height was associated with CRC risk for women (OR = 1.15, 95% CI = 1.05-1.26), but not men (OR = 0.98, 95% CI = 0.92-1.05). Consistent with these results, carrying greater numbers of (weighted) height-increasing alleles (per 1-unit increase) was associated with higher CRC risk for women and men combined (OR = 1.07, 95% CI = 1.01-1.14) and for women (OR = 1.09, 95% CI =  .01-1.19). There was weaker evidence of an association for men (OR = 1.05, 95% CI = 0.96-1.15).

Conclusion: We provide evidence for a causal association between height and CRC for women. The CRC-height association for men remains unclear and warrants further investigation in other large studies.
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http://dx.doi.org/10.1093/ije/dyv082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481609PMC
April 2015
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