Jenkins, Mark A.

Objective To estimate risk of colorectal cancer (CRC) for first-degree relatives of CRC cases based on CRC molecular subtypes and tumour pathology features. Design We studied a cohort of 33 496 first-degree relatives of 4853 incident invasive CRC cases (probands) who were recruited to the Colon Cancer Family Registry through population cancer registries in the USA, Canada and Australia. We categorised the first-degree relatives into four groups: 28 156 of 4095 mismatch repair (MMR)-proficient probands, 2302 of 301 MMR-deficient non-Lynch syndrome probands, 1799 of 271 suspected Lynch syndrome probands and 1239 of 186 Lynch syndrome probands. We compared CRC risk for first-degree relatives stratified by the absence or presence of specific tumour molecular pathology features in probands across each of these four groups and for all groups combined. Results Compared with first-degree relatives of MMR-proficient CRC cases, a higher risk of CRC was estimated for first-degree relatives of CRC cases with suspected Lynch syndrome (HR 2.06, 95% CI 1.59 to 2.67) and with Lynch syndrome (HR 5.37, 95% CI 4.16 to 6.94), but not with MMR-deficient non-Lynch syndrome (HR 1.04, 95% CI 0.82 to 1.31). A greater risk of CRC was estimated for first-degree relatives if CRC cases were diagnosed before age 50 years, had proximal colon cancer or if their tumours had any of the following: expanding tumour margin, peritumoral lymphocytes, tumour-infiltrating lymphocytes or synchronous CRC. Conclusions Molecular pathology features are potentially useful to refine screening recommendations for first-degree relatives of CRC cases and to identify which cases are more likely to be caused by genetic or other familial factors.

Abstract Background: Both shorter and longer telomeres in peripheral blood leukocyte (PBL) DNA have been associated with cancer risk. However, associations remain inconsistent across studies of the same cancer type. This study compares DNA preparation methods to determine telomere length from patients with colorectal cancer. Methods: We examined PBL relative telomere length (RTL) measured by quantitative PCR (qPCR) in 1,033 patients with colorectal cancer and 2,952 healthy controls. DNA was extracted with phenol/chloroform, PureGene, or QIAamp. Results: We observed differences in RTL depending on DNA extraction method (P < 0.001). Phenol/chloroform-extracted DNA had a mean RTL (T/S ratio) of 0.78 (range 0.01–6.54) compared with PureGene-extracted DNA (mean RTL of 0.75; range 0.00–12.33). DNA extracted by QIAamp yielded a mean RTL of 0.38 (range 0.02–3.69). We subsequently compared RTL measured by qPCR from an independent set of 20 colorectal cancer cases and 24 normal controls in PBL DNA extracted by each of the three extraction methods. The range of RTL measured by qPCR from QIAamp-extracted DNA (0.17–0.58) was less than from either PureGene or phenol/chloroform (ranges, 0.04–2.67 and 0.32–2.81, respectively). Conclusions: RTL measured by qPCR from QIAamp-extracted DNA was less than from either PureGene or phenol/chloroform (P < 0.001). Impact: Differences in DNA extraction method may contribute to the discrepancies between studies seeking to find an association between the risk of cancer or other diseases and RTL. Cancer Epidemiol Biomarkers Prev; 22(11); 2047–54. ©2013 AACR.

Objective Genome-wide association studies have identified a large number of single nucleotide polymorphisms (SNPs) associated with a wide array of cancer sites. Several of these variants demonstrate associations with multiple cancers, suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesised that SNPs previously associated with other cancers may additionally be associated with colorectal cancer. In a large-scale study, we examined 171 SNPs previously associated with 18 different cancers for their associations with colorectal cancer. Design We examined 13 338 colorectal cancer cases and 40 967 controls from three consortia: Population Architecture using Genomics and Epidemiology (PAGE), Genetic Epidemiology of Colorectal Cancer (GECCO), and the Colon Cancer Family Registry (CCFR). Study-specific logistic regression results, adjusted for age, sex, principal components of genetic ancestry, and/or study specific factors (as relevant) were combined using fixed-effect meta-analyses to evaluate the association between each SNP and colorectal cancer risk. A Bonferroni-corrected p value of 2.92×10 −4 was used to determine statistical significance of the associations. Results Two correlated SNPs—rs10090154 and rs4242382—in Region 1 of chromosome 8q24, a prostate cancer susceptibility region, demonstrated statistically significant associations with colorectal cancer risk. The most significant association was observed with rs4242382 (meta-analysis OR=1.12; 95% CI 1.07 to 1.18; p=1.74×10 −5 ), which also demonstrated similar associations across racial/ethnic populations and anatomical sub-sites. Conclusions This is the first study to clearly demonstrate Region 1 of chromosome 8q24 as a susceptibility locus for colorectal cancer; thus, adding colorectal cancer to the list of cancer sites linked to this particular multicancer risk region at 8q24.

Abstract Background: The Colorectal Cancer Family Registry (Colon CFR) has served as an international resource for studies of the genetics and epidemiology of colorectal cancer (CRC) since 1997. It is the largest family-based resource in the world for the study of CRC and other cancers, such as endometrial cancer, that occur in CRC families. The Colon CFR has recruited participants via six institutions: Cancer Care Ontario, Fred Hutchinson Cancer Research Center, Mayo Clinic, University of Hawaii, University of Southern California Consortium, and University of Melbourne. Methods: CRC cases were recruited from both population-based cancer registries and family cancer clinics. Controls were recruited from population-based sources. Relatives were recruited via cases and controls. Participants were asked to: donate a blood sample; give permission to access any tumor tissue; complete a detailed personal and family history of cancer including degree of relationship, site of cancer and age of diagnosis; and complete a detailed baseline lifestyle questionnaire that was administered across all recruitment sites, which included items on established and suspected risk factors for colorectal cancer: personal characteristics including age, sex, height and weight, country of birth, ethnicity, race and religion; history of exercise, alcohol consumption and smoking; medication use including NSAIDs, cholesterol-lowering agents, diabetes medication and post- menopausal hormone use; history of colorectal cancer screening including fecal occult blood test, sigmoidoscopy, colonoscopy; personal history of surgery including polypectomy, other bowel surgery and hysterectomy; frequency of meat consumption and method of cooking; reproductive history (for women). Participants were also asked for detail information on the frequency of food consumption and portion size using a food frequency questionnaire. Follow-up of participants has been conducted every five years, by questionnaire, to update vital status, surgery, cancer screening, polypectomy, and personal and family history of cancer history. Participants have been characterized for major known predisposing CRC gene mutations and have undergone a genome-wide SNP testing and tested for known CRC SNPs. Results: The Colon CFR has enrolled 35,297 participants (11,635 affected with CRC, 3,629 affected with other cancers, and 20,033 unaffected) who have completed baseline questionnaires. We have 5-year follow-up data on 24,692 participants (6,329 affected with CRC, 2,261 affected with other cancers, and 16,102 unaffected) and 10-year follow-up data on 10,467 (3,654 affected with CRC, 1,182 affected with other cancers, and 5,631 unaffected). We have GWAS data on 3,830 participants, candidate SNP data on 18,000 participants, and mismatch repair gene mutation data on 2,697 participants (and observed 1,697 carriers with a deleterious mutation). Conclusion: This largest and best characterized CRC cohort in the world will facilitate post-GWAS research to provide insight into the role of environmental factors, and how they interact with genetic factors on CRC risk. Researchers are encouraged by the National Cancer Institute (USA) and the Colon CFR investigators to apply for access to this unique resource of data and biospecimens for collaborative research. Citation Format: Aung Ko Win, Daniel D. Buchanan, Noralane M. Lindor, Robert W. Haile, Polly A. Newcomb, Loic Le Marchand, Steven Gallinger, Hopper L. John, Casey Graham, Mark A. Jenkins. The Colon Cancer Family Registry: A major resource for post-GWAS gene-environment studies. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 43.

Abstract Background: Colorectal cancer (CRC) in densely affected families without Lynch Syndrome may be due to mutations in undiscovered genetic loci. Familial linkage analyses have yielded disparate results; the use of exome sequencing in coding regions may identify novel segregating variants. Methods: We completed exome sequencing on 40 affected cases from 16 multicase pedigrees to identify novel loci. Variants shared among all sequenced cases within each family were identified and filtered to exclude common variants and single-nucleotide variants (SNV) predicted to be benign. Results: We identified 32 nonsense or splice-site SNVs, 375 missense SNVs, 1,394 synonymous or noncoding SNVs, and 50 indels in the 16 families. Of particular interest are two validated and replicated missense variants in CENPE and KIF23, which are both located within previously reported CRC linkage regions, on chromosomes 1 and 15, respectively. Conclusions: Whole-exome sequencing identified DNA variants in multiple genes. Additional sequencing of these genes in additional samples will further elucidate the role of variants in these regions in CRC susceptibility. Impact: Exome sequencing of familial CRC cases can identify novel rare variants that may influence disease risk. Cancer Epidemiol Biomarkers Prev; 22(7); 1239–51. ©2013 AACR.

Abstract Background: Previous reports suggest that relatives of colorectal cancer (CRC)-affected probands carrying the BRAF p.V600E mutation are at an increased risk of CRC and extracolonic cancers (ECC). In this study, we estimated the association between a family history of either CRC or ECC and risk of CRC with a BRAF p.V600E mutation. Methods: Population-based CRC cases (probands, ages 18–59 years at diagnosis), recruited irrespective of family cancer history, were characterized for BRAF p.V600E mutation and mismatch repair (MMR) status. ORs and 95% confidence intervals (CI) were estimated using multivariable logistic regression. Results: The 690 eligible probands showed a mean age at CRC diagnosis of 46.9 ± 7.8 years, with 313 (47.9%) reporting a family history of CRC and 53 (7.7%) that were BRAF-mutated. Probands with BRAF-mutated, MMR-proficient CRCs were less likely to have a family history of CRC than probands that were BRAF wild-type (OR, 0.46; 95% CI, 0.24–0.91; P = 0.03). For probands with a BRAF-mutated CRC, the mean age at diagnosis was greater for those with a CRC-affected first- or second-degree relative (49.3 ± 6.4 years) compared with those without a family history (43.8 ± 10.2 years; P = 0.04). The older the age at diagnosis of CRC with the BRAF p.V600E mutation, the more likely these probands were to show a family history of CRC (OR, 1.09 per year of age; 95% CI, 1.00–1.18; P = 0.04). Conclusions: Probands with early-onset, BRAF-mutated, and MMR-proficient CRC were less likely to have a family history of CRC than probands that were BRAF-wild-type. Impact: These findings provide useful insights for cancer risk assessment in families and suggest that familial or inherited factors are more important in early-onset, BRAF-wild-type CRC. Cancer Epidemiol Biomarkers Prev; 22(5); 917–26. ©2013 AACR.

Abstract A substantial proportion of familial colorectal cancer (CRC) is not a consequence of known susceptibility loci, such as mismatch repair (MMR) genes, supporting the existence of additional loci. To identify novel CRC loci, we conducted a genome-wide linkage scan in 356 white families with no evidence of defective MMR (i.e., no tumors with loss of expression of MMR proteins; no microsatellite instability (MSI)-high tumors, and no evidence of linkage to MMR genes). This represents the largest linkage analysis of proficient MMR (pMMR) familial CRC to date. Families were ascertained via the NCI-supported Colon Cancer Family Registry multi-site (Colon CFR) consortium, the City of Hope, and Memorial University of Newfoundland. A total of 1,612 individuals (average 5.0 per family, range 2-10 with an average of 2.2 affected and 2.8 unaffected individuals) were genotyped using genome-wide single nucleotide polymorphism linkage arrays; parametric and non-parametric linkage analysis used MERLIN in a priori-defined family groups. Five lod scores greater than 3.0 were observed, accounting for heterogeneity, in four chromosomal regions. The greatest lod scores were at 4q21.1 among families with mean age of diagnosis less than 50 years (dominant HLOD=4.51, α=0.84, 145.40 cM, rs10518142) and at 12q24.32 among all families (dominant HLOD=3.60, α=0.48, 285.15 cM, rs952093). Among families with four or more affected individuals and among clinic-based families, a common peak was observed at 15q22.31 (101.40 cM, rs1477798; dominant HLOD=3.07, α=0.29; dominant HLOD=3.03, α=0.32, respectively). Analysis of families with only two affected individuals yielded a peak at 8q13.2 (recessive HLOD=3.02, α=0.51, 132.52 cM, rs1319036). These linkage regions comprise previously unreported loci, supporting the hypothesis that novel loci contribute to CRC in familial pMMR cases. These loci are also largely distinct from those identified in case-control GWAS. To follow up on these findings, a custom Agilent Sure Select Target Enrichment panel has been designed for genes in three of these regions, in order to sequence probands using an Illumina HiSeq 2000. This study demonstrates the utility of family-based data and provides evidence for additional alleles for familial CRC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2930. doi:1538-7445.AM2012-2930