Cholecystectomy and the risk of colorectal cancer by tumor mismatch repair deficiency status

PURPOSE

Gallbladder diseases and cholecystectomy may play a role in the development of colorectal cancer (CRC). Our aim was to investigate the association between cholecystectomy and CRC risk overall and by sex, family history, anatomical location, and tumor mismatch repair (MMR) status.

METHODS

This study comprised 5847 incident CRC cases recruited from population cancer registries in Australia, Canada, and the USA into the Colon Cancer Family Registry between 1997 and 2012 and 4970 controls with no personal history of CRC who were either randomly selected from the general population or were spouses of the cases. The association between cholecystectomy and CRC was estimated using logistic regression, after adjusting for confounding factors.

RESULTS

Overall, there was no evidence for an association between cholecystectomy and CRC (odds ratio [OR] = 0.88, 95 % confidence interval 0.73, 1.08). In the stratified analyses, there was no evidence for a difference in the association between women and men (P = 0.54), between individuals with and without family history of CRC in first-degree relative (P = 0.64), between tumor anatomical locations (P = 0.45), or between MMR-proficient and MMR-deficient cases (P = 0.54).

CONCLUSION

Cholecystectomy is not a substantial risk factor for CRC, regardless of sex, family history, anatomical location, or tumor MMR status.

Common variants in the obesity-associated genes FTO and MC4R are not associated with risk of colorectal cancer

BACKGROUND

Obesity is a convincing risk factor for colorectal cancer. Genetic variants in or near FTO and MC4R are consistently associated with body mass index and other body size measures, but whether they are also associated with colorectal cancer risk is unclear.

METHODS

In the discovery stage, we tested associations of 677 FTO and 323 MC4R single nucleotide polymorphisms (SNPs) 100kb upstream and 300kb downstream from each respective locus with risk of colorectal cancer in data from the Colon Cancer Family Registry (CCFR: 1960 cases; 1777 controls). Next, all SNPs that were nominally statistically significant (p<0.05) in the discovery stage were included in replication analyses in data from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO: 9716 cases; 9844 controls).

RESULTS

In the discovery stage, 43 FTO variants and 18 MC4R variants were associated with colorectal cancer risk (p<0.05). No SNPs remained statistically significant in the replication analysis after accounting for multiple comparisons.

CONCLUSION

We found no evidence that individual variants in or near the obesity-related genes FTO and MC4R are associated with risk of colorectal cancer.

Abstract LB-360: Association between weight change after colorectal cancer diagnosis and long-term mortality differs by age

Previous studies evaluating the association of weight gain following colorectal cancer (CRC) diagnosis with mortality have been inconsistent. In this study, we evaluate whether this association differs by age at diagnosis.

Incident, invasive CRC cases were identified from the Puget Sound Surveillance, Epidemiology and End Results (SEER) Registry from 1997-2008 and enrolled in the Seattle Colon Cancer Family Registry. A standardized interview (at mean 8 months after diagnosis) ascertained self-reported height and weight two years prior. A follow-up questionnaire was administered approximately 5 years after baseline, with 1,087 participants providing height and weight at both time points. Survival outcomes were assessed through linkage to the National Death Index. Delayed-entry Cox regression was used to estimate the association between change in weight (kg) and all-cause or CRC-specific mortality (Hazard Ratio (HR) and 95% Confidence Interval (95% CI)), with survival time beginning at the 5-year follow-up survey. Models adjusted for age at diagnosis, sex, smoking history (ever/never), cancer stage at diagnosis (I-IV, missing), days from diagnosis and baseline survey, and body mass index (kg/m2) at baseline. Analyses were stratified by age at diagnosis (&lt;50 or ?50 years). We also evaluated an interaction term between age at diagnosis (continuous) and per-kg weight change.

Over a median 4.7 years (range 0-9.0) of follow-up after the 5-year survey, 234 participants died (69 from CRC). At the 5-year follow-up, 579 (54%) participants had lost weight (median -5 kg), 114 (11%) reported the same weight, and 385 (36%) had gained weight (median 4 kg).

Among those aged &lt;50 at CRC diagnosis, weight gain at follow-up was significantly associated with higher subsequent all-cause mortality (HR = 1.19 per 5kg, 95% CI: 1.02-1.39), but not CRC-specific mortality. Among those aged ?50 at CRC diagnosis, weight gain at the follow-up time point was significantly associated with higher CRC-specific mortality (HR = 1.34 per 5kg, 95% CI: 1.11-1.61), but not all-cause. The association between weight change and survival differed by age for CRC-specific mortality (P-interaction = 0.01) but not all-cause mortality (P-interaction = 0.82). These findings support the importance of maintaining a healthy body weight after CRC diagnosis, and may suggest the association of weight change with risk of cause-specific death differs in individuals younger versus older than age 50 at diagnosis.

Citation Format: Jonathan M. Kocarnik, Xinwei Hua, Jamaica Robinson, Amanda I. Phipps, Stacey Cohen, Polly A. Newcomb. Association between weight change after colorectal cancer diagnosis and long-term mortality differs by age. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-360.

Abstract 5214: Stage IV colorectal cancer sub-site and patterns of distant metastases

Approximately 20% of individuals diagnosed with colorectal cancer (CRC) in the United States are found to have distant metastases at the time of their diagnosis, indicating an extremely poor prognosis. Although it is well known that primary CRC typically metastasizes to the liver and/or lungs, little is known regarding which factors might explain the anatomic pattern of CRC metastatic spread. Using population-based registry data from the Surveillance, Epidemiology and End Results (SEER) cancer registry of the Seattle-Puget Sound region, we assessed the relationship between primary CRC sub-site and the presence of synchronous metastases in the liver, lungs, and both the liver and lungs. All individuals with stage IV CRC who were diagnosed between 2010-2014 in the 13-county catchment area and who also had complete data on site of metastasis at diagnosis were included in analyses (N = 1287). In total, 703 (55%) patients had distant metastases confined to the liver at the time of diagnosis, 78 (6%) had lung-only metastases, 190 (15%) had metastases in both the liver and lungs but not at other sites, and 316 (25%) exhibited different patterns of metastatic spread, including to the bone, brain, and other anatomic sites. Using multiple logistic regression models, we compared individuals with different patterns of metastatic spread at diagnosis with respect to primary CRC site and with separate models comparing cases with liver-only metastases to all other metastatic cases, comparing cases with lung-only metastases to all other metastatic cases, and comparing cases with metastases to both the liver and lungs to all other metastatic CRC cases. All models were adjusted for age at diagnosis and sex, as well as for depth of primary tumor growth within the colorectum (T-stage) and extent of cancer spread to lymph nodes (N-stage). The odds of having a primary CRC tumor in the rectum, versus proximal colon, were significantly lower among patients with liver-only synchronous metastases relative to those with other patterns of metastatic spread at diagnosis [odds ratio (OR): 0.62, 95% confidence interval (CI): 0.46 - 0.82]. Conversely, the odds of having a primary CRC located in the rectum were significantly higher among those with metastatic disease confined to the lungs (OR: 2.48, 95% CI: 1.38 - 4.47) and those with metastases to the liver and lungs (OR: 1.97, 95% CI: 1.29 - 3.01). Our findings suggest that a patient's site of primary CRC may be informative with respect to possible pattern of metastatic spread.

Citation Format: Jamaica R. Robinson, Polly A. Newcomb, Sheetal Hardikar, Stacey A. Cohen, Amanda I. Phipps. Stage IV colorectal cancer sub-site and patterns of distant metastases. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5214.

Racial Patterns of Peripheral T-Cell Lymphoma Incidence and Survival in the United States

PURPOSE

To compare incidence and survival of peripheral T-cell lymphoma (PTCL) subtypes among US racial/ethnic groups.

METHODS

Patients with PTCL (age ≥ 15 years; 2000 to 2012) were identified in the Surveillance, Epidemiology, and End Results (SEER) registries. Race/ethnicity was categorized as non-Hispanic white, black, Asian/Pacific Islander, Hispanic white, or American Indian/Alaskan native. Age-standardized annual incidence rates and incidence rate ratios were estimated with 95% CIs, and case-case odds ratios were estimated by race/ethnicity using polytomous regression. Survival was estimated from SEER follow-up data with Cox regression.

RESULTS

Thirteen thousand one hundred seven patients with PTCL were identified. Annual PTCL incidence was highest in blacks and lowest in Native Americans. Compared with non-Hispanic whites, blacks had a higher incidence of PTCL not otherwise specified (PTCL-NOS), anaplastic large-cell lymphoma, and adult T-cell leukemia/lymphoma (ATLL) and a lower incidence of angioimmunoblastic T-cell lymphoma (AITL); Asians/Pacific Islanders had a higher incidence of AITL, extranodal nasal-type natural killer/T-cell lymphoma and NK-cell leukemia (ENKCL), and ATLL and a lower incidence of anaplastic large-cell lymphoma; Hispanics had a higher incidence of AITL and ENKCL; and Native Americans had a lower incidence of PTCL-NOS (all P < .05). The ratio of ENKCL to PCTL-NOS among Native Americans, Asians/Pacific Islanders, and Hispanic whites was approximately three- to four-fold the same ratio among non-Hispanic whites. Survival varied significantly by race/ethnicity (P < .001), with blacks in particular experiencing shorter survival for most subtypes.

CONCLUSION

Striking variation in incidence, proportions of PTCL subtypes, and survival was observed. Aspects of these PTCL subtype patterns, such as for ENKCL and ATLL, were similar to corresponding global populations. Despite the small population size and limited number of Native American patients, PTCL subtype frequencies in this group were distinct but most similar to Hispanic whites. Survival disparities were evident, especially for blacks compared with non-Hispanic whites.

Abstract 5230: Large scale whole genome sequencing with imputation into GWAS improves our understanding of the genetic architecture of colorectal cancer

Whole-genome sequencing (WGS) has started a new era in human genetics in which data can be used to more fully understand the role of genetic variation in common complex diseases, including the role of less frequent and rare variants and structural variation. To explore the impact of these variants on colorectal cancer risk we conducted the first large scale WGS study for colorectal cancer (CRC) including 1,961 CRC cases and 981 controls. These WGS data as well as those from the Haplotype Reference Consortium were imputed in 13,104 CRC cases and 15,521 controls with genome-wide association study (GWAS) data that are part of the Colorectal Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Focusing on rare and less frequent variants, insertions and deletions we observed potentially novel variants: a less frequent variant (MAF = 0.026) on chromosome 5 located in NREP/STARD4-AS1 (p = value 4E-08); and a novel rare multi-allelic variant (MAF = 0.003) on chromosome 9 near KLF9 and TRPM3 (p-value 2E-09; the other allele of this multi-allelic variant had a MAF of 0.0003 and p-value of 0.55). Furthermore, we observed an independent locus close to the known region 8q24 that was located upstream of GSDMC (MAF = 0.16, p-value 5E-08). Within the known region 8q23/EIF3H we identified several low frequency variants with similar MAF (0.0181 to 0.0204) including a 6bp deletion with p-values between 4E-08 and 1E-09 that were independent of the common variant signal in this region. In addition, we identified statistically significant (p&lt;5E-08) deletions, insertions, and an essential splice site within known GWAS loci that present interesting candidates for functional studies. We will follow up these findings in independent samples from the Colorectal Cancer Transdisciplinary Study (CORECT) and CCFR, as well as additional samples currently genotyped in GECCO. In conclusion, next generation sequencing combined with imputation in large GWAS data sets has the potential to identify novel low frequency and rare genetic variants, aid fine-mapping of known CRC susceptibility loci and point to interesting functional candidates.

Citation Format: Jeroen Huyghe, Sai Chen, Hyun M. Kang, Tabitha A. Harrison, Sonja I. Berndt, Stephane Bézieau, Hermann Brenner, Graham Casey, Andrew T. Chan, Jenny Chang-Claude, Gallinger J. Steven, Stephen B. Gruber, Andrea Gsur, Michael Hoffmeister, Thomas J. Hudson, Loic Le Marchand, Polly A. Newcomb, John D. Potter, Conghui Qu, Martha L. Slattery, Joshua D. Smith, Emily White, Li Hsu, Goncalo R. Abecasis, Deborah A. Nickerson, Ulrike Peters. Large scale whole genome sequencing with imputation into GWAS improves our understanding of the genetic architecture of colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5230.

Abstract 4489: Using functional data from Roadmap Epigenomics to inform analysis of rare variants linked to gene expression in a large colorectal cancer study

To investigate the role of low frequency and rare genetic variation in colorectal cancer (CRC) susceptibility, the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and the Colorectal Cancer Family Registry (CCFR) conducted whole genome sequencing and imputed into genome-wide association studies (GWAS) of 14,718 CRC cases and 12,186 controls. These data provide a unique opportunity to investigate rare variants, which contribute to the majority of the variation in the genome. To improve power for discovering rare CRC susceptibility variants (&lt;1% MAF), Roadmap Epigenomics data were used to construct biologically relevant testing sets of enhancers, promoters and exons for gene-based association testing across the genome. Since enhancers exert their effects by impacting expression of target genes, we defined enhancer-gene networks by linking enhancer(s) to target gene expression using Roadmap chromatin state maps and gene expression. Variants in linked enhancers from digestive and immune tissues were aggregated together with variants in the promoter and non-synonymous coding variants in the target gene. We tested 9,884 variant sets for association with CRC risk using the Mixed effects Score Test (MiST). Our most significant findings are for acyl-Coenzyme A dehydrogenase, C-2 to C-3 short chain precursor-ACADS (p = 1×10−4), AlkB homologs, including AlkB homolog 1-ALKBH1 (p = 2×10−4), and SRA stem-loop interacting RNA binding protein-SLIRP (p = 2×10−4). We will replicate these findings within the Colorectal Cancer Transdisciplinary Study (CORECT), as well as additional samples currently genotyped in CCFR and GECCO (over 25,000 CRC cases and controls). Although the top findings are statistically non-significant in this initial dataset, each of these genes linked to molecular pathways implicated in CRC carcinogenesis (fatty acid metabolism, DNA/RNA repair, and Nuclear Receptor signaling pathway, which interacts with the Wnt, beta-catenin pathways to result in a diverse array of cellular effects including altered cellular adhesion, tissue morphogenesis, and oncogenesis). Our current findings suggest that although functional insight can improve power for novel discovery, even larger sample sizes and/or pathway-based analyses are necessary to understand the role of rare variants in CRC carcinogenesis.

Citation Format: Stephanie A. Bien, Tabitha A. Harrison, Paul L. Auer, Flora Qu, Jeroen Huyghe, Barbara Banbury, Peyton Greenside, Goncalo R. Abecasis, Sonja I. Berndt, Stephane Bézieau, Hermann Brenner, Graham Casey, Andrew T. Chan, Jenny Chang-Claude, Sai Chen, Joshua D. Smith, Loic Le Marchand, Christopher Carlson, Polly A. Newcomb, Christian Fuchsberger, Marty L. Slattery, Hyun M. Kang, Emily White, John Potter, Steven J. Gallinger, Michael Hoffmeister, Stephen B. Gruber, Deborah A. Nickerson, Ulrike Peters, Anshul Kundaje, Li Hsu. Using functional data from Roadmap Epigenomics to inform analysis of rare variants linked to gene expression in a large colorectal cancer study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4489.

Mendelian randomisation analysis strongly implicates adiposity with risk of developing colorectal cancer

BACKGROUND

Observational studies have associated adiposity with an increased risk of colorectal cancer (CRC). However, such studies do not establish a causal relationship. To minimise bias from confounding we performed a Mendelian randomisation (MR) analysis to examine the relationship between adiposity and CRC.

METHODS

We used SNPs associated with adult body mass index (BMI), waist-hip ratio (WHR), childhood obesity and birth weight as instrumental variables in a MR analysis of 9254 CRC cases and 18 386 controls.

RESULTS

In the MR analysis, the odds ratios (ORs) of CRC risk per unit increase in BMI, WHR and childhood obesity were 1.23 (95% CI: 1.02-1.49, P=0.033), 1.59 (95% CI: 1.08-2.34, P=0.019) and 1.07 (95% CI: 1.03-1.13, P=0.018), respectively. There was no evidence for association between birth weight and CRC (OR=1.22, 95% CI: 0.89-1.67, P=0.22). Combining these data with a concurrent MR-based analysis for BMI and WHR with CRC risk (totalling to 18 190 cases, 27 617 controls) provided increased support, ORs for BMI and WHR were 1.26 (95% CI: 1.10-1.44, P=7.7 × 10(-4)) and 1.40 (95% CI: 1.14-1.72, P=1.2 × 10(-3)), respectively.

CONCLUSIONS

These data provide further evidence for a strong causal relationship between adiposity and the risk of developing CRC highlighting the urgent need for prevention and treatment of adiposity.

Reliability of plasma lipopolysaccharide-binding protein (LBP) from repeated measures in healthy adults

Plasma lipopolysaccharide-binding protein (LBP), a measure of internal exposure to bacterial lipopolysaccharide, has been associated with several chronic conditions and may be a marker of chronic inflammation; however, no studies have examined the reliability of this biomarker in a healthy population. We examined the temporal reliability of LBP measured in archived samples from participants in two studies. In Study one, 60 healthy participants had blood drawn at two time points: baseline and follow-up (either three, six, or nine months). In Study two, 24 individuals had blood drawn three to four times over a seven-month period. We measured LBP in archived plasma by ELISA. Test-retest reliability was estimated by calculating the intraclass correlation coefficient (ICC). Plasma LBP concentrations showed moderate reliability in Study one (ICC 0.60, 95 % CI 0.43-0.75) and Study two (ICC 0.46, 95 % CI 0.26-0.69). Restricting the follow-up period improved reliability. In Study one, the reliability of LBP over a three-month period was 0.68 (95 % CI: 0.41-0.87). In Study two, the ICC of samples taken ≤seven days apart was 0.61 (95 % CI 0.29-0.86). Plasma LBP concentrations demonstrated moderate test-retest reliability in healthy individuals with reliability improving over a shorter follow-up period.

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

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).

Identification of independent association signals and putative functional variants for breast cancer risk through fine-scale mapping of the 12p11 locus

BACKGROUND

Multiple recent genome-wide association studies (GWAS) have identified a single nucleotide polymorphism (SNP), rs10771399, at 12p11 that is associated with breast cancer risk.

METHOD

We performed a fine-scale mapping study of a 700 kb region including 441 genotyped and more than 1300 imputed genetic variants in 48,155 cases and 43,612 controls of European descent, 6269 cases and 6624 controls of East Asian descent and 1116 cases and 932 controls of African descent in the Breast Cancer Association Consortium (BCAC; http://bcac.ccge.medschl.cam.ac.uk/ ), and in 15,252 BRCA1 mutation carriers in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Stepwise regression analyses were performed to identify independent association signals. Data from the Encyclopedia of DNA Elements project (ENCODE) and the Cancer Genome Atlas (TCGA) were used for functional annotation.

RESULTS

Analysis of data from European descendants found evidence for four independent association signals at 12p11, represented by rs7297051 (odds ratio (OR) = 1.09, 95 % confidence interval (CI) = 1.06-1.12; P = 3 × 10(-9)), rs805510 (OR = 1.08, 95 % CI = 1.04-1.12, P = 2 × 10(-5)), and rs1871152 (OR = 1.04, 95 % CI = 1.02-1.06; P = 2 × 10(-4)) identified in the general populations, and rs113824616 (P = 7 × 10(-5)) identified in the meta-analysis of BCAC ER-negative cases and BRCA1 mutation carriers. SNPs rs7297051, rs805510 and rs113824616 were also associated with breast cancer risk at P < 0.05 in East Asians, but none of the associations were statistically significant in African descendants. Multiple candidate functional variants are located in putative enhancer sequences. Chromatin interaction data suggested that PTHLH was the likely target gene of these enhancers. Of the six variants with the strongest evidence of potential functionality, rs11049453 was statistically significantly associated with the expression of PTHLH and its nearby gene CCDC91 at P < 0.05.

CONCLUSION

This study identified four independent association signals at 12p11 and revealed potentially functional variants, providing additional insights into the underlying biological mechanism(s) for the association observed between variants at 12p11 and breast cancer risk.

Variation at 2q35 (PNKD and TMBIM1) influences colorectal cancer risk and identifies a pleiotropic effect with inflammatory bowel disease

To identify new risk loci for colorectal cancer (CRC), we conducted a meta-analysis of seven genome-wide association studies (GWAS) with independent replication, totalling 13 656 CRC cases and 21 667 controls of European ancestry. The combined analysis identified a new risk association for CRC at 2q35 marked by rs992157 (P = 3.15 × 10-8, odds ratio = 1.10, 95% confidence interval = 1.06-1.13), which is intronic to PNKD (paroxysmal non-kinesigenic dyskinesia) and TMBIM1 (transmembrane BAX inhibitor motif containing 1). Intriguingly this susceptibility single-nucleotide polymorphism (SNP) is in strong linkage disequilibrium (r2 = 0.90, D' = 0.96) with the previously discovered GWAS SNP rs2382817 for inflammatory bowel disease (IBD). Following on from this observation we examined for pleiotropy, or shared genetic susceptibility, between CRC and the 200 established IBD risk loci, identifying an additional 11 significant associations (false discovery rate [FDR]) < 0.05). Our findings provide further insight into the biological basis of inherited genetic susceptibility to CRC, and identify risk factors that may influence the development of both CRC and IBD.

Association of a let-7 miRNA binding region of TGFBR1 with hereditary mismatch repair proficient colorectal cancer (MSS HNPCC)

The purpose of this study was to identify novel colorectal cancer (CRC)-causing alleles in unexplained familial CRC cases. In order to do so, coding regions in five candidate genes (MGMT, AXIN2, CTNNB1, TGFBR1 and TGFBR2) were sequenced in 11 unrelated microsatellite-stable hereditary non-polyposis CRC (MSS HNPCC) cases. Selected genetic variants were genotyped in a discovery set of 27 MSS HNPCC cases and 85 controls. One genetic variant, rs67687202, in TGFBR1 emerged as significant (P = 0.002), and it was genotyped in a replication set of 87 additional MSS HNPCC-like cases and 338 controls where it was also significantly associated with MSS HNPCC cases (P = 0.041). In the combined genotype data, rs67687202 was associated with a moderate increase in CRC risk (OR = 1.68; 95% CI = 1.13-2.50; P = 0.010). We tested a highly correlated SNP rs868 in 723 non-familial CRC cases compared with 629 controls, and it was not significantly associated with CRC risk (P = 0.370). rs868 is contained in a let-7 miRNA binding site in the 3'UTR of TGFBR1, which might provide a functional basis for the association in MSS HNPCC. In luciferase assays, the risk-associated allele for rs868 was associated with half the luciferase expression in the presence of miRNA let-7b-5p compared with protective allele, suggesting more binding of let-7b-5p and less TGFBR1 expression. Thus, rs868 potentially is a CRC risk-causing allele. Our results support the concept that rs868 is associated with lower TGFBR1 expression thereby increasing CRC risk.

Relationship of prediagnostic body mass index with survival after colorectal cancer: Stage-specific associations

Higher body mass index (BMI) is a well-established risk factor for colorectal cancer (CRC), but is inconsistently associated with CRC survival. In 6 prospective studies participating in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), 2,249 non-Hispanic white CRC cases were followed for a median 4.5 years after diagnosis, during which 777 died, 554 from CRC-related causes. Associations between prediagnosis BMI and survival (overall and CRC-specific) were evaluated using Cox regression models adjusted for age at diagnosis, sex, study and smoking status (current/former/never). The association between BMI category and CRC survival varied by cancer stage at diagnosis (I-IV) for both all-cause (p-interaction = 0.03) and CRC-specific mortality (p-interaction = 0.04). Compared to normal BMI (18.5-24.9 kg/m(2) ), overweight (BMI 25.0-29.9) was associated with increased mortality among those with Stage I disease, and decreased mortality among those with Stages II-IV disease. Similarly, obesity (BMI ≥30) was associated with increased mortality among those with Stages I-II disease, and decreased mortality among those with Stages III-IV disease. These results suggest the relationship between BMI and survival after CRC diagnosis differs by stage at diagnosis, and may emphasize the importance of adequate metabolic reserves for colorectal cancer survival in patients with late-stage disease.

Urinary Cadmium and Risk of Invasive Breast Cancer in the Women's Health Initiative

Cadmium is a widespread heavy metal pollutant that may act as an exogenous estrogenic hormone. Environmental cadmium exposure has been associated with risk of breast cancer in retrospective studies. We prospectively assessed the relationship between cadmium exposure, evaluated by creatinine-normalized urinary cadmium concentration, and invasive breast cancer among 12,701 postmenopausal women aged ≥50 years in a Women's Health Initiative study of bone mineral density. After a median of 13.2 years of follow-up (1993-2010), 508 cases of invasive breast cancer and 1,050 comparison women were identified for a case-cohort analysis. Multivariable Cox regression was used to calculate hazard ratios and 95% confidence intervals. Risk of breast cancer was not associated with urinary cadmium parameterized either in quartiles (comparing highest quartile with lowest, hazard ratio = 0.80, 95% confidence interval: 0.56, 1.14; P for trend = 0.20) or as a log-transformed continuous variable (per 2-fold higher urinary cadmium concentration, hazard ratio = 0.94, 95% confidence interval: 0.86, 1.03). We did not observe an association between urinary cadmium and breast cancer risk in any subgroup examined, including never smokers and women with body mass index (weight (kg)/height (m)(2)) less than 25. Results were consistent in both estrogen receptor-positive and estrogen receptor-negative tumors. Our results do not support the hypothesis that environmental cadmium exposure is associated with risk of postmenopausal breast cancer.

Urinary cadmium and estimated dietary cadmium in the Women's Health Initiative

Cadmium, a heavy metal dispersed in the environment as a result of industrial and agricultural applications, has been implicated in several human diseases including renal disease, cancers, and compromised bone health. In the general population, the predominant sources of cadmium exposure are tobacco and diet. Urinary cadmium (uCd) reflects long-term exposure and has been frequently used to assess cadmium exposure in epidemiological studies; estimated dietary intake of cadmium (dCd) has also been used in several studies. The validity of dCd in comparison with uCd is unclear. This study aimed to compare dCd, estimated from food frequency questionnaires, to uCd measured in spot urine samples from 1,002 participants of the Women's Health Initiative. Using linear regression, we found that dCd was not statistically significantly associated with uCd (β=0.006, P-value=0.14). When stratified by smoking status, dCd was not significantly associated with uCd both in never smokers (β=0.006, P-value=0.09) and in ever smokers (β=0.003, P-value=0.67). Our results suggest that because of the lack of association between estimated dCd and measured uCd, dietary estimation of cadmium exposure should be used with caution in epidemiologic studies.

Trends in Health-Related Quality of Life After a Diagnosis of Ductal Carcinoma In Situ

PURPOSE

Studies of quality of life (QoL) are scarce among survivors of ductal carcinoma in situ (DCIS). The objective of this study was to assess long-term QoL in DCIS survivors in relation to age at diagnosis, time since diagnosis, and treatments received.

METHODS

We assessed physical and mental measures of health-related QoL in 1,604 patients with DCIS diagnosed in 1997 to 2006 with up to four follow-up interviews. We further compared baseline QoL to 1,055 control patients without DCIS. QoL was measured using the validated Medical Outcomes Study Short Form 36 Health Status Survey questionnaire. Among patients with DCIS, we examined trends in QoL over time since diagnosis using generalized linear regression models, adjusting for confounders. We tested for effect modification by surgical treatment choice, post-treatment endocrine therapy use, and age at diagnosis.

RESULTS

Both physical and mental measures of QoL among DCIS survivors at fewer than 2 years after diagnosis were comparable to controls. Mental measures of QoL among patients with DCIS declined at ≥ 10 years after diagnosis and were significantly lower than at less than 2 years after diagnosis (47.4 v 52.0; P < .01). In the first 5 years after a DCIS diagnosis, mental QoL was significantly higher among women diagnosed at ages 50 to 74 years compared with those diagnosed at ages 28 to 49 years, although this difference was not sustained in later time periods.

CONCLUSION

QoL after a DCIS diagnosis was generally comparable to that of women of similar age without a personal history of DCIS. Our findings suggest that DCIS survivors, and particularly those diagnosed at a younger age, may benefit from support for mental QoL.

Blood Lipid Concentrations and Colorectal Adenomas: A Systematic Review and Meta-Analysis of Colonoscopy Studies in Asia, 2000-2014

It is unclear whether dyslipidemia is associated with risk of colorectal neoplasia. The incidence of both conditions is increasing in Asia, motivating a number of new studies from this region. We performed a systematic literature search of Asian colonoscopy-based studies that collected blood lipid concentrations at the time of endoscopy. Persons found to have colorectal adenoma were considered cases, and those found to be adenoma-free were considered controls. Seventeen studies published between 2000 and 2014 met inclusion criteria, collectively enrolling 17,387 cases and 30,427 controls. Mean differences and adjusted odds ratios were summarized with random-effects meta-analyses. Compared with controls, cases had higher total cholesterol (mean difference (MD) = 2.4 mg/dL, 95% confidence interval (CI): 0.2, 4.6), higher low-density lipoprotein cholesterol (MD = 1.3 mg/dL, 95% CI: 0.1, 2.6), higher triglyceride (MD = 16.4 mg/dL, 95% CI: 11.2, 21.5), and lower high-density lipoprotein (HDL) cholesterol (MD = -2.1 mg/dL, 95% CI: -2.7, -1.6) concentrations. Based on adjusted odds ratios, associations for 40-mg/dL-higher triglyceride levels (odds ratio = 1.13, 95% CI: 1.05, 1.21) and 10-mg/dL-higher HDL cholesterol levels (odds ratio = 0.96, 95% CI: 0.92, 1.00) achieved statistical significance. Persons with adenoma were more likely to have unfavorable cholesterol profiles at the time of colonoscopy than those without adenoma. The most convincing evidence for an association between dyslipidemia and colorectal neoplasia was observed for hypertriglyceridemia.

Multivitamin, calcium and folic acid supplements and the risk of colorectal cancer in Lynch syndrome

BACKGROUND

People with a DNA mismatch repair (MMR) gene mutation have a substantially elevated risk of colorectal cancer (CRC) but the modifiers of this risk are not well established. We investigated the association between dietary supplement intake and CRC risk for carriers.

METHODS

This study included 1966 (56% female) carriers of an MMR gene mutation (719 MLH1, 931 MSH2, 211 MSH6 and 105 PMS2) who were recruited from the USA, Canada, Australia and New Zealand into the Colon Cancer Family Registry between 1997 and 2012. Information on lifestyle factors including supplement intake was collected at the time of recruitment. Using Cox proportional hazards regression weighted to correct for ascertainment bias, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between self-reported multivitamin, calcium and folic acid supplement intake and CRC risk.

RESULTS

Of 744 carriers with CRC, 18%, 6% and 5% reported intake of multivitamin, calcium and folic acid supplements for at least 1 month, respectively, compared with 27%, 11% and 10% of 1222 carriers without CRC. After adjusting for identified confounding variables, a decreased CRC risk was associated with multivitam inintake for at least 3 years (HR 0.47, 95% CI 0.32-0.69) and calcium intake for at least 3 years(HR 0.42, 95% CI 0.23-0.74), compared with never users. There was no evidence of an association between folic acid supplement intake and CRC risk (P = 0.82).

CONCLUSION

Intake of multivitamin and calcium supplements might be associated with a decreased risk of CRC for MMR gene mutation carriers.

Determining the familial risk distribution of colorectal cancer: a data mining approach

This study was aimed to characterize the distribution of colorectal cancer risk using family history of cancers by data mining. Family histories for 10,066 colorectal cancer cases recruited to population cancer registries of the Colon Cancer Family Registry were analyzed using a data mining framework. A novel index was developed to quantify familial cancer aggregation. Artificial neural network was used to identify distinct categories of familial risk. Standardized incidence ratios (SIRs) and corresponding 95% confidence intervals (CIs) of colorectal cancer were calculated for each category. We identified five major, and 66 minor categories of familial risk for developing colorectal cancer. The distribution the major risk categories were: (1) 7% of families (SIR = 7.11; 95% CI 6.65-7.59) had a strong family history of colorectal cancer; (2) 13% of families (SIR = 2.94; 95% CI 2.78-3.10) had a moderate family history of colorectal cancer; (3) 11% of families (SIR = 1.23; 95% CI 1.12-1.36) had a strong family history of breast cancer and a weak family history of colorectal cancer; (4) 9 % of families (SIR = 1.06; 95 % CI 0.96-1.18) had strong family history of prostate cancer and weak family history of colorectal cancer; and (5) 60% of families (SIR = 0.61; 95% CI 0.57-0.65) had a weak family history of all cancers. There is a wide variation of colorectal cancer risk that can be categorized by family history of cancer, with a strong gradient of colorectal cancer risk between the highest and lowest risk categories. The risk of colorectal cancer for people with the highest risk category of family history (7% of the population) was 12-times that for people in the lowest risk category (60%) of the population. Data mining was proven an effective approach for gaining insight into the underlying cancer aggregation patterns and for categorizing familial risk of colorectal cancer.

Germline TP53 Mutations in Patients With Early-Onset Colorectal Cancer in the Colon Cancer Family Registry

IMPORTANCE

Li-Fraumeni syndrome, usually characterized by germline TP53 mutations, is associated with markedly elevated lifetime risks of multiple cancers, and has been linked to an increased risk of early-onset colorectal cancer.

OBJECTIVE

To examine the frequency of germline TP53 alterations in patients with early-onset colorectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

This was a multicenter cross-sectional cohort study of individuals recruited to the Colon Cancer Family Registry (CCFR) from 1998 through 2007 (genetic testing data updated as of January 2015). Both population-based and clinic-based patients in the United States, Canada, Australia, and New Zealand were recruited to the CCFR. Demographic information, clinical history, and family history data were obtained at enrollment. Biospecimens were collected from consenting probands and families, including microsatellite instability and DNA mismatch repair immunohistochemistry results. A total of a 510 individuals diagnosed as having colorectal cancer at age 40 years or younger and lacking a known hereditary cancer syndrome were identified from the CCFR as being potentially eligible. Fifty-three participants were excluded owing to subsequent identification of germline mutations in DNA mismatch repair genes (n = 47) or biallelic MUTYH mutations (n = 6).

INTERVENTIONS

Germline sequencing of the TP53 gene was performed. Identified TP53 alterations were assessed for pathogenicity using literature and international mutation database searches and in silico prediction models.

MAIN OUTCOMES AND MEASURES

Frequency of nonsynonymous germline TP53 alterations.

RESULTS

Among 457 eligible participants (314, population-based; 143, clinic-based; median age at diagnosis, 36 years [range, 15-40 years]), 6 (1.3%; 95% CI, 0.5%-2.8%) carried germline missense TP53 alterations, none of whom met clinical criteria for Li-Fraumeni syndrome. Four of the identified TP53 alterations have been previously described in the literature in probands with clinical features of Li-Fraumeni syndrome, and 2 were novel alterations.

CONCLUSIONS AND RELEVANCE

In a large cohort of patients with early-onset colorectal cancer, germline TP53 mutations were detected at a frequency comparable with the published prevalence of germline APC mutations in colorectal cancer. With the increasing use of multigene next-generation sequencing panels in hereditary cancer risk assessment, clinicians will be faced with the challenge of interpreting the biologic and clinical significance of germline TP53 mutations in families whose phenotypes are atypical for Li-Fraumeni syndrome.

GWASeq: targeted re-sequencing follow up to GWAS

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.

The Association Between Post-Diagnosis Health Behaviors and Quality of Life in Survivors of Ductal Carcinoma In Situ

Background: Survivors of ductal carcinoma in situ (DCIS), an early stage breast cancer, tend to decrease physical activity, gain weight, and maintain alcohol use following treatment. However, the impact of these health behaviors on long-term quality of life (QoL) in DCIS survivors has not been investigated. Methods: We examined the association of post-diagnosis body mass index (BMI), physical activity and smoking with QoL among 1,448 DCIS survivors aged 20–74, who were diagnosed during 1995–2006 and enrolled in the population-based Wisconsin In Situ Cohort. Health behaviors and QoL were self-reported during biennial post- diagnosis interviews. Physical and mental QoL were measured using the validated SF-36 questionnaire (higher scores reflect more positive QoL). Generalized linear regression was used to establish QoL mean scores in cross-sectional analyses, with multivariable adjustment for age, comorbidity status, education, and income. Results: Women reported 3,444 QoL observations over an average 7.9 years of follow-up. Physical health summary scale measures of QoL were significantly higher among women with healthy BMI (46.5 for healthy weight versus 40.5 for obese, P = 0.02) and those who were physically active (45.9 for active women versus 42.6 for inactive, P = 0.03). Mental health summary scale scores were significantly higher among non-smokers (51.2 for non-smokers versus 47.1 for current smokers, P &lt; 0.01). These associations were consistent over increasing time since treatment up to 15 years. Conclusion: Our preliminary analysis suggests that maintaining healthy behaviors following DCIS treatment is associated with improved long-term QoL. Longitudinal analysis using cross-lagged regression is underway to evaluate the temporal association between health behavior and QoL. Understanding factors that impact QoL in DCIS survivors may inform interventions aimed at preventing negative health behaviors and optimizing long term quality of life following a DCIS diagnosis.