Publications by authors named "Martha L Slattery"

342 Publications

Nongenetic Determinants of Risk for Early-Onset Colorectal Cancer.

JNCI Cancer Spectr 2021 Jun 20;5(3):pkab029. Epub 2021 May 20.

Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France.

Background: Incidence of early-onset (younger than 50 years of age) colorectal cancer (CRC) is increasing in many countries. Thus, elucidating the role of traditional CRC risk factors in early-onset CRC is a high priority. We sought to determine whether risk factors associated with late-onset CRC were also linked to early-onset CRC and whether association patterns differed by anatomic subsite.

Methods: Using data pooled from 13 population-based studies, we studied 3767 CRC cases and 4049 controls aged younger than 50 years and 23 437 CRC cases and 35 311 controls aged 50 years and older. Using multivariable and multinomial logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to assess the association between risk factors and early-onset CRC and by anatomic subsite.

Results: Early-onset CRC was associated with not regularly using nonsteroidal anti-inflammatory drugs (OR = 1.43, 95% CI = 1.21 to 1.68), greater red meat intake (OR = 1.10, 95% CI = 1.04 to 1.16), lower educational attainment (OR = 1.10, 95% CI = 1.04 to 1.16), alcohol abstinence (OR = 1.23, 95% CI = 1.08 to 1.39), and heavier alcohol use (OR = 1.25, 95% CI = 1.04 to 1.50). No factors exhibited a greater excess in early-onset compared with late-onset CRC. Evaluating risks by anatomic subsite, we found that lower total fiber intake was linked more strongly to rectal (OR = 1.30, 95% CI = 1.14 to 1.48) than colon cancer (OR = 1.14, 95% CI = 1.02 to 1.27;  = .04).

Conclusion: In this large study, we identified several nongenetic risk factors associated with early-onset CRC, providing a basis for targeted identification of those most at risk, which is imperative in mitigating the rising burden of this disease.
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http://dx.doi.org/10.1093/jncics/pkab029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8134523PMC
June 2021

Genetically Predicted Circulating C-Reactive Protein Concentration and Colorectal Cancer Survival: A Mendelian Randomization Consortium Study.

Cancer Epidemiol Biomarkers Prev 2021 May 10. Epub 2021 May 10.

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

Background: A positive association between circulating C-reactive protein (CRP) and colorectal cancer survival was reported in observational studies, which are susceptible to unmeasured confounding and reverse causality. We used a Mendelian randomization approach to evaluate the association between genetically predicted CRP concentrations and colorectal cancer-specific survival.

Methods: We used individual-level data for 16,918 eligible colorectal cancer cases of European ancestry from 15 studies within the International Survival Analysis of Colorectal Cancer Consortium. We calculated a genetic-risk score based on 52 CRP-associated genetic variants identified from genome-wide association studies. Because of the non-collapsibility of hazard ratios from Cox proportional hazards models, we used the additive hazards model to calculate hazard differences (HD) and 95% confidence intervals (CI) for the association between genetically predicted CRP concentrations and colorectal cancer-specific survival, overall and by stage at diagnosis and tumor location. Analyses were adjusted for age at diagnosis, sex, body mass index, genotyping platform, study, and principal components.

Results: Of the 5,395 (32%) deaths accrued over up to 10 years of follow-up, 3,808 (23%) were due to colorectal cancer. Genetically predicted CRP concentration was not associated with colorectal cancer-specific survival (HD, -1.15; 95% CI, -2.76 to 0.47 per 100,000 person-years; = 0.16). Similarly, no associations were observed in subgroup analyses by stage at diagnosis or tumor location.

Conclusions: Despite adequate power to detect moderate associations, our results did not support a causal effect of circulating CRP concentrations on colorectal cancer-specific survival.

Impact: Future research evaluating genetically determined levels of other circulating inflammatory biomarkers (i.e., IL6) with colorectal cancer survival outcomes is needed.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1848DOI Listing
May 2021

Genetically predicted circulating concentrations of micronutrients and risk of colorectal cancer among individuals of European descent: a Mendelian randomization study.

Am J Clin Nutr 2021 06;113(6):1490-1502

Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Background: The literature on associations of circulating concentrations of minerals and vitamins with risk of colorectal cancer is limited and inconsistent. Evidence from randomized controlled trials (RCTs) to support the efficacy of dietary modification or nutrient supplementation for colorectal cancer prevention is also limited.

Objectives: To complement observational and RCT findings, we investigated associations of genetically predicted concentrations of 11 micronutrients (β-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B-6, vitamin B-12, and zinc) with colorectal cancer risk using Mendelian randomization (MR).

Methods: Two-sample MR was conducted using 58,221 individuals with colorectal cancer and 67,694 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium, Colorectal Cancer Transdisciplinary Study, and Colon Cancer Family Registry. Inverse variance-weighted MR analyses were performed with sensitivity analyses to assess the impact of potential violations of MR assumptions.

Results: Nominally significant associations were noted for genetically predicted iron concentration and higher risk of colon cancer [ORs per SD (ORSD): 1.08; 95% CI: 1.00, 1.17; P value = 0.05] and similarly for proximal colon cancer, and for vitamin B-12 concentration and higher risk of colorectal cancer (ORSD: 1.12; 95% CI: 1.03, 1.21; P value = 0.01) and similarly for colon cancer. A nominally significant association was also noted for genetically predicted selenium concentration and lower risk of colon cancer (ORSD: 0.98; 95% CI: 0.96, 1.00; P value = 0.05) and similarly for distal colon cancer. These associations were robust to sensitivity analyses. Nominally significant inverse associations were observed for zinc and risk of colorectal and distal colon cancers, but sensitivity analyses could not be performed. None of these findings survived correction for multiple testing. Genetically predicted concentrations of β-carotene, calcium, copper, folate, magnesium, phosphorus, and vitamin B-6 were not associated with disease risk.

Conclusions: These results suggest possible causal associations of circulating iron and vitamin B-12 (positively) and selenium (inversely) with risk of colon cancer.
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http://dx.doi.org/10.1093/ajcn/nqab003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168352PMC
June 2021

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
July 2021

Adiposity, metabolites, and colorectal cancer risk: Mendelian randomization study.

BMC Med 2020 12 17;18(1):396. Epub 2020 Dec 17.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Background: Higher adiposity increases the risk of colorectal cancer (CRC), but whether this relationship varies by anatomical sub-site or by sex is unclear. Further, the metabolic alterations mediating the effects of adiposity on CRC are not fully understood.

Methods: We examined sex- and site-specific associations of adiposity with CRC risk and whether adiposity-associated metabolites explain the associations of adiposity with CRC. Genetic variants from genome-wide association studies of body mass index (BMI) and waist-to-hip ratio (WHR, unadjusted for BMI; N = 806,810), and 123 metabolites from targeted nuclear magnetic resonance metabolomics (N = 24,925), were used as instruments. Sex-combined and sex-specific Mendelian randomization (MR) was conducted for BMI and WHR with CRC risk (58,221 cases and 67,694 controls in the Genetics and Epidemiology of Colorectal Cancer Consortium, Colorectal Cancer Transdisciplinary Study, and Colon Cancer Family Registry). Sex-combined MR was conducted for BMI and WHR with metabolites, for metabolites with CRC, and for BMI and WHR with CRC adjusted for metabolite classes in multivariable models.

Results: In sex-specific MR analyses, higher BMI (per 4.2 kg/m) was associated with 1.23 (95% confidence interval (CI) = 1.08, 1.38) times higher CRC odds among men (inverse-variance-weighted (IVW) model); among women, higher BMI (per 5.2 kg/m) was associated with 1.09 (95% CI = 0.97, 1.22) times higher CRC odds. WHR (per 0.07 higher) was more strongly associated with CRC risk among women (IVW OR = 1.25, 95% CI = 1.08, 1.43) than men (IVW OR = 1.05, 95% CI = 0.81, 1.36). BMI or WHR was associated with 104/123 metabolites at false discovery rate-corrected P ≤ 0.05; several metabolites were associated with CRC, but not in directions that were consistent with the mediation of positive adiposity-CRC relations. In multivariable MR analyses, associations of BMI and WHR with CRC were not attenuated following adjustment for representative metabolite classes, e.g., the univariable IVW OR for BMI with CRC was 1.12 (95% CI = 1.00, 1.26), and this became 1.11 (95% CI = 0.99, 1.26) when adjusting for cholesterol in low-density lipoprotein particles.

Conclusions: Our results suggest that higher BMI more greatly raises CRC risk among men, whereas higher WHR more greatly raises CRC risk among women. Adiposity was associated with numerous metabolic alterations, but none of these explained associations between adiposity and CRC. More detailed metabolomic measures are likely needed to clarify the mechanistic pathways.
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http://dx.doi.org/10.1186/s12916-020-01855-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7745469PMC
December 2020

A Combined Proteomics and Mendelian Randomization Approach to Investigate the Effects of Aspirin-Targeted Proteins on Colorectal Cancer.

Cancer Epidemiol Biomarkers Prev 2021 Mar 14;30(3):564-575. Epub 2020 Dec 14.

Nutrition and Metabolism Section, International Agency for Research on Cancer, World Health Organization, Lyon, France.

Background: Evidence for aspirin's chemopreventative properties on colorectal cancer (CRC) is substantial, but its mechanism of action is not well-understood. We combined a proteomic approach with Mendelian randomization (MR) to identify possible new aspirin targets that decrease CRC risk.

Methods: Human colorectal adenoma cells (RG/C2) were treated with aspirin (24 hours) and a stable isotope labeling with amino acids in cell culture (SILAC) based proteomics approach identified altered protein expression. Protein quantitative trait loci (pQTLs) from INTERVAL ( = 3,301) and expression QTLs (eQTLs) from the eQTLGen Consortium ( = 31,684) were used as genetic proxies for protein and mRNA expression levels. Two-sample MR of mRNA/protein expression on CRC risk was performed using eQTL/pQTL data combined with CRC genetic summary data from the Colon Cancer Family Registry (CCFR), Colorectal Transdisciplinary (CORECT), Genetics and Epidemiology of Colorectal Cancer (GECCO) consortia and UK Biobank (55,168 cases and 65,160 controls).

Results: Altered expression was detected for 125/5886 proteins. Of these, aspirin decreased MCM6, RRM2, and ARFIP2 expression, and MR analysis showed that a standard deviation increase in mRNA/protein expression was associated with increased CRC risk (OR: 1.08, 95% CI, 1.03-1.13; OR: 3.33, 95% CI, 2.46-4.50; and OR: 1.15, 95% CI, 1.02-1.29, respectively).

Conclusions: MCM6 and RRM2 are involved in DNA repair whereby reduced expression may lead to increased DNA aberrations and ultimately cancer cell death, whereas ARFIP2 is involved in actin cytoskeletal regulation, indicating a possible role in aspirin's reduction of metastasis.

Impact: Our approach has shown how laboratory experiments and population-based approaches can combine to identify aspirin-targeted proteins possibly affecting CRC risk.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8086774PMC
March 2021

Identifying Novel Susceptibility Genes for Colorectal Cancer Risk From a Transcriptome-Wide Association Study of 125,478 Subjects.

Gastroenterology 2021 Mar 12;160(4):1164-1178.e6. Epub 2020 Oct 12.

Department of Cancer Biology and Genetics and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

Background And Aims: Susceptibility genes and the underlying mechanisms for the majority of risk loci identified by genome-wide association studies (GWAS) for colorectal cancer (CRC) risk remain largely unknown. We conducted a transcriptome-wide association study (TWAS) to identify putative susceptibility genes.

Methods: Gene-expression prediction models were built using transcriptome and genetic data from the 284 normal transverse colon tissues of European descendants from the Genotype-Tissue Expression (GTEx), and model performance was evaluated using data from The Cancer Genome Atlas (n = 355). We applied the gene-expression prediction models and GWAS data to evaluate associations of genetically predicted gene-expression with CRC risk in 58,131 CRC cases and 67,347 controls of European ancestry. Dual-luciferase reporter assays and knockdown experiments in CRC cells and tumor xenografts were conducted.

Results: We identified 25 genes associated with CRC risk at a Bonferroni-corrected threshold of P < 9.1 × 10, including genes in 4 novel loci, PYGL (14q22.1), RPL28 (19q13.42), CAPN12 (19q13.2), MYH7B (20q11.22), and MAP1L3CA (20q11.22). In 9 known GWAS-identified loci, we uncovered 9 genes that have not been reported previously, whereas 4 genes remained statistically significant after adjusting for the lead risk variant of the locus. Through colocalization analysis in GWAS loci, we additionally identified 12 putative susceptibility genes that were supported by TWAS analysis at P < .01. We showed that risk allele of the lead risk variant rs1741640 affected the promoter activity of CABLES2. Knockdown experiments confirmed that CABLES2 plays a vital role in colorectal carcinogenesis.

Conclusions: Our study reveals new putative susceptibility genes and provides new insight into the biological mechanisms underlying CRC development.
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http://dx.doi.org/10.1053/j.gastro.2020.08.062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7956223PMC
March 2021

Genetic Variants in the Regulatory T cell-Related Pathway and Colorectal Cancer Prognosis.

Cancer Epidemiol Biomarkers Prev 2020 12 2;29(12):2719-2728. Epub 2020 Oct 2.

Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia.

Background: High numbers of lymphocytes in tumor tissue, including T regulatory cells (Treg), have been associated with better colorectal cancer survival. Tregs, a subset of CD4 T lymphocytes, are mediators of immunosuppression in cancer, and therefore variants in genes related to Treg differentiation and function could be associated with colorectal cancer prognosis.

Methods: In a prospective German cohort of 3,593 colorectal cancer patients, we assessed the association of 771 single-nucleotide polymorphisms (SNP) in 58 Treg-related genes with overall and colorectal cancer-specific survival using Cox regression models. Effect modification by microsatellite instability (MSI) status was also investigated because tumors with MSI show greater lymphocytic infiltration and have been associated with better prognosis. Replication of significant results was attempted in 2,047 colorectal cancer patients of the International Survival Analysis in Colorectal Cancer Consortium (ISACC).

Results: A significant association of the SNP rs7524066 with more favorable colorectal cancer-specific survival [hazard ratio (HR) per minor allele: 0.83; 95% confidence interval (CI), 0.74-0.94; value: 0.0033] was replicated in ISACC (HR: 0.82; 95% CI, 0.68-0.98; value: 0.03). Suggestive evidence for association was found with two SNPs, rs16906568 and rs7845577. Thirteen SNPs with differential associations with overall survival according to MSI in the discovery analysis were not confirmed.

Conclusions: Common genetic variation in the Treg pathway implicating genes such as and was shown to be associated with prognosis of colorectal cancer patients.

Impact: The implicated genes warrant further investigation.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7976673PMC
December 2020

Postmenopausal Hormone Therapy and Colorectal Cancer Risk by Molecularly Defined Subtypes and Tumor Location.

JNCI Cancer Spectr 2020 Aug 19;4(5):pkaa042. Epub 2020 May 19.

Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.

Background: Postmenopausal hormone therapy (HT) is associated with a decreased colorectal cancer (CRC) risk. As CRC is a heterogeneous disease, we evaluated whether the association of HT and CRC differs across etiologically relevant, molecularly defined tumor subtypes and tumor location.

Methods: We pooled data on tumor subtypes (microsatellite instability status, CpG island methylator phenotype status, and mutations, pathway: adenoma-carcinoma, alternate, serrated), tumor location (proximal colon, distal colon, rectum), and HT use among 8220 postmenopausal women (3898 CRC cases and 4322 controls) from 8 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CIs) for the association of ever vs never HT use with each tumor subtype compared with controls. Models were adjusted for study, age, body mass index, smoking status, and CRC family history. All statistical tests were 2-sided.

Results: Among postmenopausal women, ever HT use was associated with a 38% reduction in overall CRC risk (OR =0.62, 95% CI = 0.56 to 0.69). This association was similar according to microsatellite instability, CpG island methylator phenotype and or status. However, the association was attenuated for tumors arising through the serrated pathway (OR = 0.81, 95% CI = 0.66 to 1.01) compared with the adenoma-carcinoma pathway (OR = 0.63, 95% CI = 0.55 to 0.73; =.04) and alternate pathway (OR = 0.61, 95% CI = 0.51 to 0.72). Additionally, proximal colon tumors had a weaker association (OR = 0.71, 95% CI = 0.62 to 0.80) compared with rectal (OR = 0.54, 95% CI = 0.46 to 0.63) and distal colon (OR = 0.57, 95% CI = 0.49 to 0.66; =.01) tumors.

Conclusions: We observed a strong inverse association between HT use and overall CRC risk, which may predominantly reflect a benefit of HT use for tumors arising through the adenoma-carcinoma and alternate pathways as well as distal colon and rectal tumors.
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http://dx.doi.org/10.1093/jncics/pkaa042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7477374PMC
August 2020

Circulating bilirubin levels and risk of colorectal cancer: serological and Mendelian randomization analyses.

BMC Med 2020 09 3;18(1):229. Epub 2020 Sep 3.

Public Health Directorate, Asturias, Spain.

Background: Bilirubin, a byproduct of hemoglobin breakdown and purported anti-oxidant, is thought to be cancer preventive. We conducted complementary serological and Mendelian randomization (MR) analyses to investigate whether alterations in circulating levels of bilirubin are associated with risk of colorectal cancer (CRC). We decided a priori to perform analyses separately in men and women based on suggestive evidence that associations may differ by sex.

Methods: In a case-control study nested in the European Prospective Investigation into Cancer and Nutrition (EPIC), pre-diagnostic unconjugated bilirubin (UCB, the main component of total bilirubin) concentrations were measured by high-performance liquid chromatography in plasma samples of 1386 CRC cases and their individually matched controls. Additionally, 115 single-nucleotide polymorphisms (SNPs) robustly associated (P < 5 × 10) with circulating total bilirubin were instrumented in a 2-sample MR to test for a potential causal effect of bilirubin on CRC risk in 52,775 CRC cases and 45,940 matched controls in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colon Cancer Family Registry (CCFR), and the Colorectal Transdisciplinary (CORECT) study.

Results: The associations between circulating UCB levels and CRC risk differed by sex (P = 0.008). Among men, higher levels of UCB were positively associated with CRC risk (odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.04-1.36; per 1-SD increment of log-UCB). In women, an inverse association was observed (OR = 0.86 (0.76-0.97)). In the MR analysis of the main UGT1A1 SNP (rs6431625), genetically predicted higher levels of total bilirubin were associated with a 7% increase in CRC risk in men (OR = 1.07 (1.02-1.12); P = 0.006; per 1-SD increment of total bilirubin), while there was no association in women (OR = 1.01 (0.96-1.06); P = 0.73). Raised bilirubin levels, predicted by instrumental variables excluding rs6431625, were suggestive of an inverse association with CRC in men, but not in women. These differences by sex did not reach formal statistical significance (P ≥ 0.2).

Conclusions: Additional insight into the relationship between circulating bilirubin and CRC is needed in order to conclude on a potential causal role of bilirubin in CRC development.
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http://dx.doi.org/10.1186/s12916-020-01703-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469292PMC
September 2020

Intake of Dietary Fruit, Vegetables, and Fiber and Risk of Colorectal Cancer According to Molecular Subtypes: A Pooled Analysis of 9 Studies.

Cancer Res 2020 10 14;80(20):4578-4590. Epub 2020 Aug 14.

Department of Internal Medicine, University of Utah, Salt Lake City, Utah.

Protective associations of fruits, vegetables, and fiber intake with colorectal cancer risk have been shown in many, but not all epidemiologic studies. One possible reason for study heterogeneity is that dietary factors may have distinct effects by colorectal cancer molecular subtypes. Here, we investigate the association of fruit, vegetables, and fiber intake with four well-established colorectal cancer molecular subtypes separately and in combination. Nine observational studies including 9,592 cases with molecular subtypes for microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and somatic mutations in and genes, and 7,869 controls were analyzed. Both case-only logistic regression analyses and polytomous logistic regression analyses (with one control set and multiple case groups) were used. Higher fruit intake was associated with a trend toward decreased risk of -mutated tumors [OR 4th vs. 1st quartile = 0.82 (95% confidence interval, 0.65-1.04)] but not -wildtype tumors [1.09 (0.97-1.22); difference as shown in case-only analysis = 0.02]. This difference was observed in case-control studies and not in cohort studies. Compared with controls, higher fiber intake showed negative association with colorectal cancer risk for cases with microsatellite stable/MSI-low, CIMP-negative, -wildtype, and -wildtype tumors ( range from 0.03 to 3.4e-03), which is consistent with the traditional adenoma-colorectal cancer pathway. These negative associations were stronger compared with MSI-high, CIMP-positive, -mutated, or -mutated tumors, but the differences were not statistically significant. These inverse associations for fruit and fiber intake may explain, in part, inconsistent findings between fruit or fiber intake and colorectal cancer risk that have previously been reported. SIGNIFICANCE: These analyses by colorectal cancer molecular subtypes potentially explain the inconsistent findings between dietary fruit or fiber intake and overall colorectal cancer risk that have previously been reported.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-0168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7572895PMC
October 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

Exploratory Genome-Wide Interaction Analysis of Nonsteroidal Anti-inflammatory Drugs and Predicted Gene Expression on Colorectal Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 09 10;29(9):1800-1808. Epub 2020 Jul 10.

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

Background: Regular use of nonsteroidal anti-inflammatory drugs (NSAID) is associated with lower risk of colorectal cancer. Genome-wide interaction analysis on single variants (G × E) has identified several SNPs that may interact with NSAIDs to confer colorectal cancer risk, but variations in gene expression levels may also modify the effect of NSAID use. Therefore, we tested interactions between NSAID use and predicted gene expression levels in relation to colorectal cancer risk.

Methods: Genetically predicted gene expressions were tested for interaction with NSAID use on colorectal cancer risk among 19,258 colorectal cancer cases and 18,597 controls from 21 observational studies. A Mixed Score Test for Interactions (MiSTi) approach was used to jointly assess G × E effects which are modeled via fixed interaction effects of the weighted burden within each gene set (burden) and residual G × E effects (variance). A false discovery rate (FDR) at 0.2 was applied to correct for multiple testing.

Results: Among the 4,840 genes tested, genetically predicted expression levels of four genes modified the effect of any NSAID use on colorectal cancer risk, including (P = 1.96 × 10), (P = 2.3 × 10), (P = 9.38 × 10), and (P = 1.44 × 10). There was a significant interaction between expression level of and regular use of aspirin only on colorectal cancer risk (P = 3.23 × 10). No interactions were observed between predicted gene expression and nonaspirin NSAID use at FDR < 0.2.

Conclusions: By incorporating functional information, we discovered several novel genes that interacted with NSAID use.

Impact: These findings provide preliminary support that could help understand the chemopreventive mechanisms of NSAIDs on colorectal cancer.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-1018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7556991PMC
September 2020

Telomere Maintenance Variants and Survival after Colorectal Cancer: Smoking- and Sex-Specific Associations.

Cancer Epidemiol Biomarkers Prev 2020 09 25;29(9):1817-1824. Epub 2020 Jun 25.

Department of Epidemiology, University of Washington, Seattle, Washington.

Background: Telomeres play an important role in colorectal cancer prognosis. Variation in telomere maintenance genes may be associated with survival after colorectal cancer diagnosis, but evidence is limited. In addition, possible interactions between telomere maintenance genes and prognostic factors, such as smoking and sex, also remain to be investigated.

Methods: We conducted gene-wide analyses of colorectal cancer prognosis in 4,896 invasive colorectal cancer cases from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO); 1,871 common variants within 13 telomere maintenance genes were included. Cox models were fit to estimate associations of these variants individually with overall and colorectal cancer-specific survival. Likelihood ratio tests were used to test for interaction by smoking and sex. values were adjusted using Bonferroni correction.

Results: The association between minor allele of rs7200950 () with colorectal cancer-specific survival varied significantly by smoking pack-years (corrected = 0.049), but no significant trend was observed. By sex, minor alleles for rs2975843 (), rs75676021 (), and rs74429678 () were associated with decreased overall and/or colorectal cancer-specific survival in women but not in men.

Conclusions: Our study reported a gene-wide statistically significant interaction with sex (). Although significant interaction by smoking pack-years () was observed, there was no evidence of a dose response. Validation of these findings in other large studies and further functional annotation on these SNPs are warranted.

Impact: Our study found a gene-smoking and gene-sex interaction on survival after colorectal cancer diagnosis, providing new insights into the role of genetic polymorphisms in telomere maintenance on colorectal cancer prognosis.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-1507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928192PMC
September 2020

Association of Body Mass Index With Colorectal Cancer Risk by Genome-Wide Variants.

J Natl Cancer Inst 2021 01;113(1):38-47

Department of Community Medicine and Epidemiology, Lady Davis Carmel Medical Center, Haifa, Israel.

Background: Body mass index (BMI) is a complex phenotype that may interact with genetic variants to influence colorectal cancer risk.

Methods: We tested multiplicative statistical interactions between BMI (per 5 kg/m2) and approximately 2.7 million single nucleotide polymorphisms with colorectal cancer risk among 14 059 colorectal cancer case (53.2% women) and 14 416 control (53.8% women) participants. All analyses were stratified by sex a priori. Statistical methods included 2-step (ie, Cocktail method) and single-step (ie, case-control logistic regression and a joint 2-degree of freedom test) procedures. All statistical tests were two-sided.

Results: Each 5 kg/m2 increase in BMI was associated with higher risks of colorectal cancer, less so for women (odds ratio [OR] = 1.14, 95% confidence intervals [CI] = 1.11 to 1.18; P = 9.75 × 10-17) than for men (OR = 1.26, 95% CI = 1.20 to 1.32; P = 2.13 × 10-24). The 2-step Cocktail method identified an interaction for women, but not men, between BMI and a SMAD7 intronic variant at 18q21.1 (rs4939827; Pobserved = .0009; Pthreshold = .005). A joint 2-degree of freedom test was consistent with this finding for women (joint P = 2.43 × 10-10). Each 5 kg/m2 increase in BMI was more strongly associated with colorectal cancer risk for women with the rs4939827-CC genotype (OR = 1.24, 95% CI = 1.16 to 1.32; P = 2.60 × 10-10) than for women with the CT (OR = 1.14, 95% CI = 1.09 to 1.19; P = 1.04 × 10-8) or TT (OR = 1.07, 95% CI = 1.01 to 1.14; P = .02) genotypes.

Conclusion: These results provide novel insights on a potential mechanism through which a SMAD7 variant, previously identified as a susceptibility locus for colorectal cancer, and BMI may influence colorectal cancer risk for women.
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http://dx.doi.org/10.1093/jnci/djaa058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781451PMC
January 2021

Functional informed genome-wide interaction analysis of body mass index, diabetes and colorectal cancer risk.

Cancer Med 2020 05 24;9(10):3563-3573. Epub 2020 Mar 24.

Department of Health Science Research, Mayo Clinic, Scottsdale, AZ, USA.

Background: Body mass index (BMI) and diabetes are established risk factors for colorectal cancer (CRC), likely through perturbations in metabolic traits (e.g. insulin resistance and glucose homeostasis). Identification of interactions between variation in genes and these metabolic risk factors may identify novel biologic insights into CRC etiology.

Methods: To improve statistical power and interpretation for gene-environment interaction (G × E) testing, we tested genetic variants that regulate expression of a gene together for interaction with BMI (kg/m ) and diabetes on CRC risk among 26 017 cases and 20 692 controls. Each variant was weighted based on PrediXcan analysis of gene expression data from colon tissue generated in the Genotype-Tissue Expression Project for all genes with heritability ≥1%. We used a mixed-effects model to jointly measure the G × E interaction in a gene by partitioning the interactions into the predicted gene expression levels (fixed effects), and residual G × E effects (random effects). G × BMI analyses were stratified by sex as BMI-CRC associations differ by sex. We used false discovery rates to account for multiple comparisons and reported all results with FDR <0.2.

Results: Among 4839 genes tested, genetically predicted expressions of FOXA1 (P = 3.15 × 10 ), PSMC5 (P = 4.51 × 10 ) and CD33 (P = 2.71 × 10 ) modified the association of BMI on CRC risk for men; KIAA0753 (P = 2.29 × 10 ) and SCN1B (P = 2.76 × 10 ) modified the association of BMI on CRC risk for women; and PTPN2 modified the association between diabetes and CRC risk in both sexes (P = 2.31 × 10 ).

Conclusions: Aggregating G × E interactions and incorporating functional information, we discovered novel genes that may interact with BMI and diabetes on CRC risk.
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http://dx.doi.org/10.1002/cam4.2971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221445PMC
May 2020

Genetic Predictors of Circulating 25-Hydroxyvitamin D and Prognosis after Colorectal Cancer.

Cancer Epidemiol Biomarkers Prev 2020 06 18;29(6):1128-1134. Epub 2020 Mar 18.

Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany.

Background: Low serum 25-hydroxyvitamin D [25(OH)D] concentrations in patients with colorectal cancer have been consistently associated with higher mortality in observational studies. It is unclear whether low 25(OH)D levels directly influence colorectal cancer mortality. To minimize bias, we use genetic variants associated with vitamin D levels to evaluate the association with overall and colorectal cancer-specific survival.

Methods: Six genetic variants have been robustly identified to be associated with 25(OH)D levels in genome-wide association studies. On the basis of data from the International Survival Analysis in Colorectal Cancer Consortium, the individual genetic variants and a weighted genetic risk score were tested for association with overall and colorectal cancer-specific survival using Cox proportional hazards models in 7,657 patients with stage I to IV colorectal cancer, of whom 2,438 died from any cause and 1,648 died from colorectal cancer.

Results: The 25(OH)D decreasing allele of SNP rs2282679 ( gene, encodes group-specific component/vitamin D-binding protein) was associated with poorer colorectal cancer-specific survival, although not significant after multiple-testing correction. None of the other five SNPs showed an association. The genetic risk score showed nonsignificant associations with increased overall [HR = 1.54; confidence interval (CI), 0.86-2.78] and colorectal cancer-specific mortality (HR = 1.76; 95% CI, 0.86-3.58). A significant increased risk of overall mortality was observed in women (HR = 3.26; 95% CI, 1.45-7.33; = 0.01) and normal-weight individuals (HR = 4.14; 95% CI, 1.50-11.43, = 0.02).

Conclusions: Our results provided little evidence for an association of genetic predisposition of lower vitamin D levels with increased overall or colorectal cancer-specific survival, although power might have been an issue.

Impact: Further studies are warranted to investigate the association in specific subgroups.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-1409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269850PMC
June 2020

Association Between Molecular Subtypes of Colorectal Tumors and Patient Survival, Based on Pooled Analysis of 7 International Studies.

Gastroenterology 2020 06 20;158(8):2158-2168.e4. Epub 2020 Feb 20.

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

Background And Aims: The heterogeneity among colorectal tumors is probably due to differences in developmental pathways and might associate with patient survival times. We studied the relationship among markers of different subtypes of colorectal tumors and patient survival.

Methods: We pooled data from 7 observational studies, comprising 5010 patients with colorectal cancer. All the studies collected information on microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and mutations in KRAS and BRAF in tumors. Tumors with complete marker data were classified as type 1 (MSI-high, CIMP-positive, with pathogenic mutations in BRAF but not KRAS), type 2 (not MSI-high, CIMP-positive, with pathogenic mutations in BRAF but not KRAS), type 3 (not MSI-high or CIMP, with pathogenic mutations in KRAS but not BRAF), type 4 (not MSI-high or CIMP, no pathogenic mutations in BRAF or KRAS), or type 5 (MSI-high, no CIMP, no pathogenic mutations in BRAF or KRAS). We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CIs) for associations of these subtypes and tumor markers with disease-specific survival (DSS) and overall survival times, adjusting for age, sex, stage at diagnosis, and study population.

Results: Patients with type 2 colorectal tumors had significantly shorter time of DSS than patients with type 4 tumors (HR 1.66; 95% CI 1.33-2.07), regardless of sex, age, or stage at diagnosis. Patients without MSI-high tumors had significantly shorter time of DSS compared with patients with MSI-high tumors (HR 0.42; 95% CI 0.27-0.64), regardless of other tumor markers or stage, or patient sex or age.

Conclusions: In a pooled analysis of data from 7 observational studies of patients with colorectal cancer, we found that tumor subtypes, defined by combinations of 4 common tumor markers, were associated with differences in survival time. Colorectal tumor subtypes might therefore be used in determining patients' prognoses.
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http://dx.doi.org/10.1053/j.gastro.2020.02.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7282955PMC
June 2020

Menstrual and reproductive characteristics and breast cancer risk by hormone receptor status and ethnicity: The Breast Cancer Etiology in Minorities study.

Int J Cancer 2020 10 29;147(7):1808-1822. Epub 2020 Feb 29.

Department of Preventive Medicine, Keck School of Medicine of USC, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA.

We pooled multiethnic data from four population-based studies and examined associations of menstrual and reproductive characteristics with breast cancer (BC) risk by tumor hormone receptor (HR) status [defined by estrogen receptor (ER) and progesterone receptor (PR)]. We estimated odds ratios and 95% confidence intervals using multivariable logistic regression, stratified by age (<50, ≥50 years) and ethnicity, for 5,186 HR+ (ER+ or PR+) cases, 1,365 HR- (ER- and PR-) cases and 7,480 controls. For HR+ BC, later menarche and earlier menopause were associated with lower risk in non-Hispanic whites (NHWs) and Hispanics, and higher parity and longer breast-feeding were associated with lower risk in Hispanics and Asian Americans, and suggestively in NHWs. Positive associations with later first full-term pregnancy (FTP), longer interval between menarche and first FTP and shorter time since last FTP were limited to younger Hispanics and Asian Americans. Except for nulliparity, reproductive characteristics were not associated with risk in African Americans. For HR- BC, lower risk was associated with later menarche, except in African Americans and older Asian Americans and with longer breast-feeding in Hispanics and Asian Americans only. In younger African Americans, HR- BC risk associated with higher parity (≥3 vs. 1 FTP) was increased fourfold in women who never breast-fed, but not in those with a breast-feeding history, suggesting that breast-feeding may mitigate the adverse effect of higher parity in younger African American women. Further work needs to evaluate why menstrual and reproductive risk factors vary in importance according to age and ethnicity.
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http://dx.doi.org/10.1002/ijc.32923DOI Listing
October 2020

Mendelian Randomization of Circulating Polyunsaturated Fatty Acids and Colorectal Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 04 12;29(4):860-870. Epub 2020 Feb 12.

Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.

Background: Results from epidemiologic studies examining polyunsaturated fatty acids (PUFA) and colorectal cancer risk are inconsistent. Mendelian randomization may strengthen causal inference from observational studies. Given their shared metabolic pathway, examining the combined effects of aspirin/NSAID use with PUFAs could help elucidate an association between PUFAs and colorectal cancer risk.

Methods: Information was leveraged from genome-wide association studies (GWAS) regarding PUFA-associated SNPs to create weighted genetic scores (wGS) representing genetically predicted circulating blood PUFAs for 11,016 non-Hispanic white colorectal cancer cases and 13,732 controls in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Associations per SD increase in the wGS were estimated using unconditional logistic regression. Interactions between PUFA wGSs and aspirin/NSAID use on colorectal cancer risk were also examined.

Results: Modest colorectal cancer risk reductions were observed per SD increase in circulating linoleic acid [OR = 0.96; 95% confidence interval (CI) = 0.93-0.98; = 5.2 × 10] and α-linolenic acid (OR = 0.95; 95% CI = 0.92-0.97; = 5.4 × 10), whereas modest increased risks were observed for arachidonic (OR = 1.06; 95% CI = 1.03-1.08; = 3.3 × 10), eicosapentaenoic (OR = 1.04; 95% CI = 1.01-1.07; = 2.5 × 10), and docosapentaenoic acids (OR = 1.03; 95% CI = 1.01-1.06; = 1.2 × 10). Each of these effects was stronger among aspirin/NSAID nonusers in the stratified analyses.

Conclusions: Our study suggests that higher circulating shorter-chain PUFAs (i.e., LA and ALA) were associated with reduced colorectal cancer risk, whereas longer-chain PUFAs (i.e., AA, EPA, and DPA) were associated with an increased colorectal cancer risk.

Impact: The interaction of PUFAs with aspirin/NSAID use indicates a shared colorectal cancer inflammatory pathway. Future research should continue to improve PUFA genetic instruments to elucidate the independent effects of PUFAs on colorectal cancer.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-0891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7125012PMC
April 2020

Physical activity and risks of breast and colorectal cancer: a Mendelian randomisation analysis.

Nat Commun 2020 01 30;11(1):597. Epub 2020 Jan 30.

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

Physical activity has been associated with lower risks of breast and colorectal cancer in epidemiological studies; however, it is unknown if these associations are causal or confounded. In two-sample Mendelian randomisation analyses, using summary genetic data from the UK Biobank and GWA consortia, we found that a one standard deviation increment in average acceleration was associated with lower risks of breast cancer (odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.27 to 0.98, P-value = 0.04) and colorectal cancer (OR: 0.66, 95% CI: 0.48 to 0.90, P-value = 0.01). We found similar magnitude inverse associations for estrogen positive (ER) breast cancer and for colon cancer. Our results support a potentially causal relationship between higher physical activity levels and lower risks of breast cancer and colorectal cancer. Based on these data, the promotion of physical activity is probably an effective strategy in the primary prevention of these commonly diagnosed cancers.
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http://dx.doi.org/10.1038/s41467-020-14389-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992637PMC
January 2020

Circulating Levels of Insulin-like Growth Factor 1 and Insulin-like Growth Factor Binding Protein 3 Associate With Risk of Colorectal Cancer Based on Serologic and Mendelian Randomization Analyses.

Gastroenterology 2020 04 27;158(5):1300-1312.e20. Epub 2019 Dec 27.

Department of Cancer Biology and Genetics and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

Background & Aims: Human studies examining associations between circulating levels of insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3) and colorectal cancer risk have reported inconsistent results. We conducted complementary serologic and Mendelian randomization (MR) analyses to determine whether alterations in circulating levels of IGF1 or IGFBP3 are associated with colorectal cancer development.

Methods: Serum levels of IGF1 were measured in blood samples collected from 397,380 participants from the UK Biobank, from 2006 through 2010. Incident cancer cases and cancer cases recorded first in death certificates were identified through linkage to national cancer and death registries. Complete follow-up was available through March 31, 2016. For the MR analyses, we identified genetic variants associated with circulating levels of IGF1 and IGFBP3. The association of these genetic variants with colorectal cancer was examined with 2-sample MR methods using genome-wide association study consortia data (52,865 cases with colorectal cancer and 46,287 individuals without [controls]) RESULTS: After a median follow-up period of 7.1 years, 2665 cases of colorectal cancer were recorded. In a multivariable-adjusted model, circulating level of IGF1 associated with colorectal cancer risk (hazard ratio per 1 standard deviation increment of IGF1, 1.11; 95% confidence interval [CI] 1.05-1.17). Similar associations were found by sex, follow-up time, and tumor subsite. In the MR analyses, a 1 standard deviation increment in IGF1 level, predicted based on genetic factors, was associated with a higher risk of colorectal cancer risk (odds ratio 1.08; 95% CI 1.03-1.12; P = 3.3 × 10). Level of IGFBP3, predicted based on genetic factors, was associated with colorectal cancer risk (odds ratio per 1 standard deviation increment, 1.12; 95% CI 1.06-1.18; P = 4.2 × 10). Colorectal cancer risk was associated with only 1 variant in the IGFBP3 gene region (rs11977526), which also associated with anthropometric traits and circulating level of IGF2.

Conclusions: In an analysis of blood samples from almost 400,000 participants in the UK Biobank, we found an association between circulating level of IGF1 and colorectal cancer. Using genetic data from 52,865 cases with colorectal cancer and 46,287 controls, a higher level of IGF1, determined by genetic factors, was associated with colorectal cancer. Further studies are needed to determine how this signaling pathway might contribute to colorectal carcinogenesis.
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http://dx.doi.org/10.1053/j.gastro.2019.12.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152801PMC
April 2020

Combined effect of modifiable and non-modifiable risk factors for colorectal cancer risk in a pooled analysis of 11 population-based studies.

BMJ Open Gastroenterol 2019 2;6(1):e000339. Epub 2019 Dec 2.

Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York, USA.

Objective: 'Environmental' factors associated with colorectal cancer (CRC) risk include modifiable and non-modifiable variables. Whether those with different non-modifiable baseline risks will benefit similarly from reducing their modifiable CRC risks remains unclear.

Design: Using 7945 cases and 8893 controls from 11 population-based studies, we combined 17 risk factors to characterise the overall environmental predisposition to CRC (environmental risk score (E-score)). We estimated the absolute risks (ARs) of CRC of 10 and 30 years across E-score using incidence-rate data from the Surveillance, Epidemiology, and End Results programme. We then combined the modifiable risk factors and estimated ARs across the modifiable risk score, stratified by non-modifiable risk profile based on genetic predisposition, family history and height.

Results: Higher E-score was associated with increased CRC risk (OR, 1.33; 95% CI 1.30 to 1.37). Across E-scores, 30-year ARs of CRC increased from 2.5% in the lowest quartile (Q1) to 5.9% in the highest (Q4) quartile for men, and from 2.1% to 4.5% for women. The modifiable risk score had a stronger association in those with high non-modifiable risk (relative excess risk due to interaction=1.2, 95% CI 0.5 to 1.9). For those in Q4 of non-modifiable risk, a decrease in modifiable risk reduced 30-year ARs from 8.9% to 3.4% for men and from 6.0% to 3.2% for women, a level lower or comparable to the average population risk.

Conclusions: Changes in modifiable risk factors may result in a substantial decline in CRC risk in both sexes. Those with high inherited risk may reap greater benefit from lifestyle modifications. Our results suggested comprehensive evaluation of environmental factors may facilitate CRC risk stratification.
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http://dx.doi.org/10.1136/bmjgast-2019-000339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904202PMC
December 2019

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

The functional role of miRNAs in colorectal cancer: insights from a large population-based study.

Cancer Biol Med 2019 May;16(2):211-219

Department of Internal Medicine, University of Utah, Salt Lake City 84108, UT, USA.

Identification of causal microRNAs (miRNAs) in colorectal cancer (CRC) is elusive, due to our lack of understanding of how specific miRNAs affect biological pathways and outcomes. An miRNA can regulate many mRNAs and an mRNA can be associated with many miRNAs; appreciation of these complex networks in which miRNAs operate is necessary to transition from identifying dysregulated miRNAs to identifying individual miRNAs or groups of miRNAs that are suitable for therapeutic purposes. The aim of the paper is to compile results from a population-based study ( = 1,954 cases with matched carcinoma/normal tissue) of miRNAs in CRC. The information gained allows for cohesive and comprehensive insight into miRNAs and CRC in terms of function and impact. Comparison of miRNA expression with mRNA expression from nine signaling pathways in carcinogenic processes allowed us to identify miRNA targets within a biological context. MiRNAs that directly influence mRNA expression may be effective biomarkers or therapeutic targets.
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http://dx.doi.org/10.20892/j.issn.2095-3941.2018.0514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713639PMC
May 2019

DNA repair and cancer in colon and rectum: Novel players in genetic susceptibility.

Int J Cancer 2020 01 4;146(2):363-372. Epub 2019 Jul 4.

Program in MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA.

Interindividual differences in DNA repair systems may play a role in modulating the individual risk of developing colorectal cancer. To better ascertain the role of DNA repair gene polymorphisms on colon and rectal cancer risk individually, we evaluated 15,419 single nucleotide polymorphisms (SNPs) within 185 DNA repair genes using GWAS data from the Colon Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), which included 8,178 colon cancer, 2,936 rectum cancer cases and 14,659 controls. Rs1800734 (in MLH1 gene) was associated with colon cancer risk (p-value = 3.5 × 10 ) and rs2189517 (in RAD51B) with rectal cancer risk (p-value = 5.7 × 10 ). The results had statistical significance close to the Bonferroni corrected p-value of 5.8 × 10 . Ninety-four SNPs were significantly associated with colorectal cancer risk after Binomial Sequential Goodness of Fit (BSGoF) procedure and confirmed the relevance of DNA mismatch repair (MMR) and homologous recombination pathways for colon and rectum cancer, respectively. Defects in MMR genes are known to be crucial for familial form of colorectal cancer but our findings suggest that specific genetic variations in MLH1 are important also in the individual predisposition to sporadic colon cancer. Other SNPs associated with the risk of colon cancer (e.g., rs16906252 in MGMT) were found to affect mRNA expression levels in colon transverse and therefore working as possible cis-eQTL suggesting possible mechanisms of carcinogenesis.
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http://dx.doi.org/10.1002/ijc.32516DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301215PMC
January 2020

Meta-analysis of 16 studies of the association of alcohol with colorectal cancer.

Int J Cancer 2020 02 7;146(3):861-873. Epub 2019 Jun 7.

Fred Hutchinson Cancer Research Center, Seattle, WA.

Alcohol consumption is an established risk factor for colorectal cancer (CRC). However, while studies have consistently reported elevated risk of CRC among heavy drinkers, associations at moderate levels of alcohol consumption are less clear. We conducted a combined analysis of 16 studies of CRC to examine the shape of the alcohol-CRC association, investigate potential effect modifiers of the association, and examine differential effects of alcohol consumption by cancer anatomic site and stage. We collected information on alcohol consumption for 14,276 CRC cases and 15,802 controls from 5 case-control and 11 nested case-control studies of CRC. We compared adjusted logistic regression models with linear and restricted cubic splines to select a model that best fit the association between alcohol consumption and CRC. Study-specific results were pooled using fixed-effects meta-analysis. Compared to non-/occasional drinking (≤1 g/day), light/moderate drinking (up to 2 drinks/day) was associated with a decreased risk of CRC (odds ratio [OR]: 0.92, 95% confidence interval [CI]: 0.88-0.98, p = 0.005), heavy drinking (2-3 drinks/day) was not significantly associated with CRC risk (OR: 1.11, 95% CI: 0.99-1.24, p = 0.08) and very heavy drinking (more than 3 drinks/day) was associated with a significant increased risk (OR: 1.25, 95% CI: 1.11-1.40, p < 0.001). We observed no evidence of interactions with lifestyle risk factors or of differences by cancer site or stage. These results provide further evidence that there is a J-shaped association between alcohol consumption and CRC risk. This overall pattern was not significantly modified by other CRC risk factors and there was no effect heterogeneity by tumor site or stage.
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http://dx.doi.org/10.1002/ijc.32377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6819207PMC
February 2020