| 1. |
- Campa, Daniele, et al.
(author)
-
A Comprehensive Investigation on Common Polymorphisms in the MDR1/ABCB1 Transporter Gene and Susceptibility to Colorectal Cancer
- 2012
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3
-
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.
|
|
| 2. |
- Huhn, Stefanie, et al.
(author)
-
Shared ancestral susceptibility to colorectal cancer and other nutrition related diseases
- 2012
-
In: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 13:94
-
Journal article (peer-reviewed)abstract
- Background: The majority of non-syndromic colorectal cancers (CRCs) can be described as a complex disease. A two-stage case-control study on CRC susceptibility was conducted to assess the influence of the ancestral alleles in the polymorphisms previously associated with nutrition-related complex diseases. Methods: In stage I, 28 single nucleotide polymorphisms (SNPs) were genotyped in a hospital-based Czech population (1025 CRC cases, 787 controls) using an allele-specific PCR-based genotyping system (KASPar (R)). In stage II, replication was carried out for the five SNPs with the lowest p values. The replication set consisted of 1798 CRC cases and 1810 controls from a population-based German study (DACHS). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between genotypes and CRC risk were estimated using logistic regression. To identify signatures of selection, Fay-Wu's H and Integrated Haplotype Score (iHS) were estimated. Results: In the Czech population, carriers of the ancestral alleles of AGT rs699 and CYP3A7 rs10211 showed an increased risk of CRC (OR 1.26 and 1.38, respectively; two-sided p <= 0.05), whereas carriers of the ancestral allele of ENPP1 rs1044498 had a decreased risk (OR 0.79; p <= 0.05). For rs1044498, the strongest association was detected in the Czech male subpopulation (OR 0.61; p=0.0015). The associations were not replicated in the German population. Signatures of selection were found for all three analyzed genes. Conclusions: Our study showed evidence of association for the ancestral alleles of polymorphisms in AGT and CYP3A7 and for the derived allele of a polymorphism in ENPP1 with an increased risk of CRC in Czechs, but not in Germans. The ancestral alleles of these SNPs have previously been associated with nutrition-related diseases hypertension (AGT and CYP3A7) and insulin resistance (ENPP1). Future studies may shed light on the complex genetic and environmental interactions between different types of nutrition-related diseases.
|
|
