Affiliation:
1. 1University of Southern California/Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California;
2. 2Molecular Epidemiology/Cancer Registry, Institute of Social and Preventive Medicine/Department of Pathology, University of Zurich, Switzerland; and
3. 3Department of Community, Occupational and Family Medicine, National University of Singapore, Singapore
Abstract
Abstract
Elevated levels of plasma insulin-like growth factor I (IGF-I) are a potential risk factor for several cancers, including colorectal cancer. Physiologic levels of plasma IGF-I vary greatly; this variation may be in part genetically determined. We identified two single nucleotide polymorphisms (SNP) in perfect linkage disequilibrium with each other and in partial linkage disequilibrium with a previously studied cytosine-adenine microsatellite [-969(CA)n]. We investigated one of the SNPs, -533T/C,and the 969(CA)n in relation to the risk of colorectal cancer in a case-control study nested within a cohort of Singapore Chinese (cases/controls = 290:873). The (CA)21 allele, rather than the previously implicated (CA)19 allele, was associated with a reduced risk of colorectal cancer (odds ratio for 21/21 versus all other genotypes, 0.48; 95% confidence interval, 0.28-0.84). For the -533C/T SNP, persons carrying one or more copies of the C allele had a decreased in risk of colorectal cancer compared with noncarriers (odds ratio for CC/CT versus TT, 0.58; 95% confidence interval, 0.41-0.82). This association was specific for colon, as opposed to rectal cancer and was modified by age. We also examined a functional insulin-like growth factor binding protein (IGFBP3) promoter SNP, -202 A/C, previously reported to predict serum IGFBP3 levels. Although we were able to confirm this genotype-phenotype association, the -202A/C IGFBP3 SNP was not significantly associated with colorectal cancer risk. In conclusion, we report a novel SNP in the IGF-I regulatory region that is associated with colorectal cancer risk.
Publisher
American Association for Cancer Research (AACR)
Cited by
2 articles.
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