Citations

Abstract Background: Individuals with a strong family history of colorectal cancer have significant risk for colorectal cancer, although adherence to colonoscopy screening in these groups remains low. This study assessed whether a tailored telephone counseling intervention can increase adherence to colonoscopy in members of high-risk families in a randomized, controlled trial. Methods: Eligible participants were recruited from two national cancer registries if they had a first-degree relative with colorectal cancer under age 60 or multiple affected family members, which included families that met the Amsterdam criteria for hereditary non-polyposis colon cancer (HNPCC), and if they were due for colonoscopy within 24 months. Participants were randomized to receive a tailored telephone intervention grounded in behavioral theory or a mailed packet with general information about screening. Colonoscopy status was assessed through follow-up surveys and endoscopy reports. Cox proportional hazards models were used to assess intervention effect. Results: Of the 632 participants (ages 25–80), 60% were female, the majority were White, non-Hispanic, educated, and had health insurance. Colonoscopy adherence increased 11 percentage points in the tailored telephone intervention group, compared with no significant change in the mailed group. The telephone intervention was associated with a 32% increase in screening adherence compared with the mailed intervention (HR, 1.32; P = 0.01). Conclusions: A tailored telephone intervention can effectively increase colonoscopy adherence in high-risk persons. This intervention has the potential for broad dissemination to healthcare organizations or other high-risk populations. Impact: Increasing adherence to colonoscopy among persons with increased colorectal cancer risk could effectively reduce incidence and mortality from this disease. Cancer Epidemiol Biomarkers Prev; 23(4); 601–10. ©2014 AACR.

Abstract Cigarette smoking (CS), hormone therapy (HT), and folate intake (FI) are each thought to influence colorectal cancer risk, but the underlying molecular mechanisms remain incompletely defined. The TP53 (p53) protein, encoded by the TP53 tumor-suppressor gene that is commonly mutated in colorectal cancer, can be readily assessed to differentiate biologically distinct colorectal cancer subtypes. In this prospective cohort study, we examined CS-, HT-, and FI-associated colorectal cancer risks by TP53 protein expression level among Iowa Women's Health Study (IWHS) participants. The IWHS recruited 41,836 randomly selected Iowa women, ages 55 to 69 years, with a valid driver's license at study entry in 1986. Self-reported exposure variables were assessed at baseline. Incident colorectal cancer cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected and evaluated for TP53 protein expression by immunohistochemistry. Multivariate Cox regression models were fit to estimate relative risks (RR) and 95% confidence intervals (CI) for associations between CS, HT, or FI and TP53-defined colorectal cancer subtypes. Informative environmental exposure and protein expression data were available for 492 incident colorectal cancer cases: 222 (45.1%) TP53 negative, 72 (14.6%) TP53 low, and 198 (40.2%) TP53 high. Longer duration (>5 years) of HT was inversely associated with TP53 high colorectal cancers (RR, 0.50; 95% CI, 0.27–0.94). No other statistically significant associations were observed. These data support possible heterogeneous effects from HT on TP53-related pathways of colorectal carcinogenesis in older women. Cancer Epidemiol Biomarkers Prev; 23(2); 350–5. ©2013 AACR.

AbstractBackground: It is widely accepted that chronic inflammation plays a role in the etiology of colorectal cancer. Using a two-stage design, we examined the associations between colorectal cancer and common variation in 37 key genes in the inflammation and innate immunity pathways.Methods: In the discovery stage, 2,322 discordant sibships (2,535 cases, 3,915 sibling controls) from the Colorectal Cancer Family Registry were genotyped for more than 600 tagSNPs and 99 single-nucleotide polymorphisms (SNP) were selected for further examination based on strength of association. In the second stage, 351 SNPs tagging gene regions covered by the 99 SNPs were tested in 4,783 Multiethnic Cohort subjects (2,153 cases, 2,630 controls).Results: The association between rs9858822 in the PPARG gene and colorectal cancer was statistically significant at the end of the second stage (OR per allele = 1.36, Bonferroni-adjusted P = 0.045), based on the “effective” number of markers in stage II (n = 306). The risk allele C was common (frequency 0.3) in African Americans but rare (frequency < 0.03) in whites, Japanese Americans, Latinos, and Native Hawaiians. No statistically significant heterogeneity of effects across race/ethnicity, body mass index (BMI) levels, regular aspirin use, or pack-years of smoking was detected for this SNP. Suggestive associations were also observed for several SNPs in close vicinity to rs9858822.Conclusions: Our results provide new evidence of association between PPARG variants and colorectal cancer risk.Impact: Further replication in independent samples is warranted. Cancer Epidemiol Biomarkers Prev; 22(11); 2094–101. ©2013 AACR.

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.