| 1. |
- Campa, Daniele, et al.
(author)
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A Comprehensive Investigation on Common Polymorphisms in the MDR1/ABCB1 Transporter Gene and Susceptibility to Colorectal Cancer
- 2012
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3
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Journal article (peer-reviewed)abstract
- ATP Binding Cassette B1 (ABCB1) is a transporter with a broad substrate specificity involved in the elimination of several carcinogens from the gut. Several polymorphic variants within the ABCB1 gene have been reported as modulators of ABCB1-mediated transport. We investigated the impact of ABCB1 genetic variants on colorectal cancer (CRC) risk. A hybrid tagging/functional approach was performed to select 28 single nucleotide polymorphisms (SNPs) that were genotyped in 1,321 Czech subjects, 699 CRC cases and 622 controls. In addition, six potentially functional SNPs were genotyped in 3,662 German subjects, 1,809 cases and 1,853 controls from the DACHS study. We found that three functional SNPs (rs1202168, rs1045642 and rs868755) were associated with CRC risk in the German population. Carriers of the rs1202168_T and rs868755_T alleles had an increased risk for CRC (P-trend = 0.016 and 0.029, respectively), while individuals bearing the rs1045642_C allele showed a decreased risk of CRC (P-trend = 0.022). We sought to replicate the most significant results in an independent case-control study of 3,803 subjects, 2,169 cases and 1,634 controls carried out in the North of Germany. None of the SNPs tested were significantly associated with CRC risk in the replication study. In conclusion, in this study of about 8,800 individuals we show that ABCB1 gene polymorphisms play at best a minor role in the susceptibility to CRC.
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| 2. |
- Rudolph, Anja, et al.
(author)
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Repeat polymorphisms in ESR2 and AR and colorectal cancer risk and prognosis: results from a German population-based case-control study
- 2014
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In: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 14
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Journal article (peer-reviewed)abstract
- Background: Evidence has accumulated which suggests that sex steroids influence colorectal cancer development and progression. We therefore assessed the association of repeat polymorphisms in the estrogen receptor beta gene (ESR2) and the androgen receptor gene (AR) with colorectal cancer risk and prognosis. Methods: The ESR2 CA and AR CAG repeat polymorphisms were genotyped in 1798 cases (746 female, 1052 male) and 1810 controls (732 female, 1078 male), matched for sex, age and county of residence. Colorectal cancer risk associations overall and specific for gender were evaluated using multivariate logistic regression models adjusted for sex, county of residence and age. Associations with overall and disease-specific survival were evaluated using Cox proportional hazard models adjusted for established prognostic factors (diagnosis of other cancer after colorectal cancer diagnosis, detection by screening, treatment with adjuvant chemotherapy, tumour extent, nodal status, distant metastasis, body mass index, age at diagnosis and year of diagnosis) and stratified for grade of differentiation. Heterogeneity in gender specific associations was assessed by comparing models with and without a multiplicative interaction term by means of a likelihood ratio test. Results: The average number of ESR2 CA repeats was associated with a small 5% increase in colorectal cancer risk (OR = 1.05, 95% CI 1.01-1.10) without significant heterogeneity according to gender or tumoural ESR2 expression. We found no indication for an association between the AR CAG repeat polymorphisms and risk of colorectal cancer. The ESR2 CA and AR CAG repeat polymorphisms were not associated with overall survival or disease specific survival after colorectal cancer diagnosis. Conclusions: Higher numbers of ESR2 CA repeats are potentially associated with a small increase in colorectal cancer risk. Our study does not support an association between colorectal cancer prognosis and the investigated repeat polymorphisms.
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| 3. |
- Sainz, Juan, et al.
(author)
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Effect of Type 2 Diabetes Predisposing Genetic Variants on Colorectal Cancer Risk.
- 2012
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 97:5, s. 845-851
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Journal article (peer-reviewed)abstract
- Background: The link between colorectal cancer (CRC) and type 2 diabetes mellitus (T2D) has been extensively studied. Although it is commonly accepted that T2D is a risk factor for CRC, the underlying mechanisms are still poorly understood. Research Design and Methods:Given that the genetic background contributes to both traits, it is conceivable that genetic variants associated with T2D may also influence the risk of CRC. We selected 26 T2D-related single-nucleotide polymorphisms (SNP) previously identified by genome-wide association studies and assessed their association with CRC and their interaction with known risk factors (gender, T2D, and body mass index) of CRC. Selected SNP were genotyped in 1798 CRC cases and 1810 controls from the population-based Darmkrebs: Chancen der Verhütung durch Screening (DACHS) study (Germany). Results:Patients carrying the TCF7L2_rs7903146_T allele had an increased risk of CRC (P(trend) = 0.02), whereas patients harboring the IL13_rs20541_T allele had a reduced risk (P(trend) = 0.02). A further analysis revealed gender-specific effects: the TCF7L2_rs7903146_T allele was associated with an increased risk of CRC in women (P(trend) = 0.003) but not in men (P(interaction) = 0.06); the LTA_rs1041981_A allele was associated with a decreased risk for CRC in women (P(trend) = 0.02), with an opposite effect in men (P(trend) = 0.05; P(interaction) = 0.002); the CDKAL1_rs7754840_C allele was associated with a decreased risk for CRC in men (P(trend) = 0.03), with no effect in women (P(interaction) = 0.03). The risk associated with the presence of T2D was modified both by IGF2BP2_rs4402960 and PPARγ_rs1801282 SNP (P(interaction) = 0.04 and 0.04, respectively). None of the findings were significant after correction for multiple comparisons. Conclusions:These findings suggest that T2D-related variants modify CRC risk independently and/or in an interactive manner according to the gender and the presence or absence of T2D.
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| 4. |
- Sainz, Juan, et al.
(author)
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GWAS-Identified Common Variants for Obesity Are Not Associated with the Risk of Developing Colorectal Cancer
- 2014
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In: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 23:6, s. 1125-1128
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Journal article (peer-reviewed)abstract
- Background: Observational studies have consistently associated obesity with colorectal cancer risk. Because both traits are genetically determined and share some metabolic biomarkers, we hypothesized that obesity-related polymorphisms could also influence the risk of developing colorectal cancer. Methods: We conducted a comprehensive population-based case-control study in 1,792 German colorectal cancer cases and 1,805 controls to explore associations between 28 obesogenic variants identified through genome-wide association studies (GWAS) and colorectal cancer risk. We also evaluated interactions between polymorphisms and body mass index (BMI), type II diabetes (T2D), and gender. Results: No evidence of association between obesogenic variants and colorectal cancer risk was observed after correction for multiple testing. There was only a remarkable interaction between the LTA(rs1041981) polymorphism and gender, which modified the risk of colorectal cancer [P-interaction - 0.002; males: odds ratio (OR), 1.14; 95% confidence intervals (CI), 1.00-1.30 vs. females: OR, 0.83; 95% CI, 0.71-0.97]. Conclusions: Our findings showed that obesogenic variants are not a major pathogenetic risk factor for colorectal cancer.
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