• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4559-4565
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• 2013

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA synthesis and repair. We here aimed to investigate two common polymorphisms, C677T and A1298C, with genotype and haplotype frequencies in colorectal cancer (CRC) cases among Jordanian. Materials and Methods: 131 CRC cases were studied for MTHFR C677T and A1298C polymorphisms, compared to 117 controls taken from the general population, employing the PCR-RFLP technique. Results: We found the frequency of the three different genotypes of MTHFR C677T among Jordanians to be CC: 61.7%, CT: 35.2%, and TT 3.1% among CRC cases and 50.9%, 38.8% and 10.3% among controls. Carriers of the TT genotype were less likely to have CRC (OR=0.25; 95%CI: 0.076-0.811; p=0.021) as compared to those with the CC genotype. Genotype analysis of MTHFR A12987C revealed AA: 38.9%, AC: 45%, and CC 16% among CRC cases and 37.4%, 50.4% and 12.2% among controls. There was no significant association between genetic polymorphism at this site and CRC. Haplotype analysis of MTHFR polymorphism at the two loci showed differential distribution of the TA haplotype (677T-1298A) between cases and controls. The TA haplotype was associated with a decreased risk for colorectal cancer (OR=0.6; 95% CI: 0.4-0.9, p=0.03). Conclusions: The genetic polymorphism of MTHFR at 677 and the TA haplotype may modulate the risk for CRC development among the Jordanian population. Our findings may reflect an importance of genes involved in folate metabolism in cancer risk.

• 한국환경보건학회지
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• 제37권6호
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• pp.429-439
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• 2011

Objectives: Ethylene oxide (EtO) is classified as a human carcinogen, but EtO is still widely used to sterilize heat-sensitive materials in hospitals. Employees working around sterilizers are exposed to EtO after sterilization. The aim of the present study was to assess the exposure of EtO level, coupled with occupationally induced micronuclei from hospital workers. The influence of genetic polymorphisms of detoxifying genes (GSTT1 and GSTM1) and DNA repair genes (XRCC1 and XRCC3) on the frequencies of micronuclei in relation to exposure of EtO was also investigated. Methods: The study population was composed of 35 occupationally exposed workers to EtO, 18 student controls and 44 unexposed hospital controls in Korea. Exposure to EtO is measured by passive personal samplers. We analyzed the frequencies of micronuclei by performing cytokinesis-block micronucleus assay (CBMN assay) and GSTM1, GSTT1, XRCC1, and XRCC3 were also genotyped by performing polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequencies of micronuclei in EtO exposure group, student controls and hospital controls were $18.00{\pm}7.73$, $10.47{\pm}7.96$ and $13.86{\pm}6.35$ respectively and their differences were statistically significant, but no significant differences according to the level of EtO were observed. There was a dose-response relationship between the frequencies of micronuclei and cumulative dose of EtO, but no significantly differences were observed. We also investigated the influence of genetic polymorphisms (GSTM1, GSTT1, XRCC1, and XRCC3) on the frequencies of micronuclei, but there were no differences in the frequencies of micronuclei by genetic polymorphisms. Conclusions: The frequencies of micronuclei in EtO exposure group was significantly higher than control groups. A dose-response relationship was found between the level of EtO exposure and the frequencies of micronuclei, but no statistically differences were observed. We also found that the frequencies of micronuclei were increased according to cumulative EtO level. There was no association of the genetic GSTM1, GSTT1, XRCC1, and XRCC3 state with the frequency of micronuclei induced by EtO exposure.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권4호
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• pp.373-382
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• 2000

Individual genetic susceptibilities to cancers may result from several factors including differences in xenobiotics metabolism to chemical carcinogens, DNA repair, altered oncogenes and suppressor genes, and environmental carcinogen exposures. Among them, genetic polymorphisms of metabolizing enzymes to chemical carcinogens have been recognized as a major important host factors in human cancers. They have two main types of enzymes: the phase I cytochrome P-450 mediating enzymes (CYPs) and phase II conjugating enzymes. The purpose of this study is to determine the frequencies of genotypes of phase I (CYP1A1 and CYP2E1) and phase II (NAT2) metabolizing enzymes in healthy control and head and neck cancer patients of Korean and to identify the relative high risk genotypes of these metabolizing enzymes to head and neck cancer in Korean. The author has analyzed 132 head and neck cancer patients and 113 healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results were as following; 1. The frequencies of genotypes of CYP1A1, CYP2E1 and NAT2 in healthy control were as following; CYP1A1 exon 7 polymorphism; Ile/Ile: Ile/Val: Val/Val = 59.3%: 36.3%: 4.4% CYP2E1 Pst I polymorphism, C1/C1: C1/C2: C2/C2 = 61.1%: 32.1%: 6.2% NAT2 polymorphism; F/F: F/S: S/S = 43.4%: 48.7%: 8.0% 2. In analysis of phase I enzyme, Val/Val genotype in CYP1A1 exon 7 polymorphism and C2/C2 genotype in CYP2E1 Pst I polymorphism were associated with relative high risks to head and neck cancers (Odds' ratio: 2.09 and 1.37, respectively). 3. Among the genotypes of NAT2 enzyme polymorphism, S/S genotype of NAT2 enzyme had 1.03 times of relative risk to head and neck cancers. 4. In combined genotyping of CYP1A1, CYP2E1, and NAT2 enzymes polymorphisms, the patients with Val/Val and C1/C1, C2/C2 and fast acetylator, and Val/Val and fast acetylator had higher relative risks than the patients with each baseline of combined genotypes (Odds' ratio: 2.82, 1.98 and 2.1, respectively). These results suggest the combined genotypes of Val/Val and C1/C1, C2/C2 and fast acetylator, and Val/Val and fast acetylator were more susceptible to head and neck cancers in Korean. And genotyping of metabolizing enzymes could be useful for predicting individual susceptibility to head and neck cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.619-624
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• 2013

Background: Colorectal cancer (CRC) exists in a more common sporadic form and less common hereditary forms, associated with the Lynch syndrome, familial adenomatous polyposis (FAP) and other rare syndromes. Sporadic CRC is believed to arise as a result of close interaction between environmental factors, including dietary and lifestyle habits, and genetic predisposition factors. In contrast, hereditary forms such as those related to the Lynch syndrome result from inheritance of germline mutations of mismatch repair (MMR) genes. However, in certain cases, the influence of low penetrance alleles in familial colorectal cancer susceptibility is also undeniable. Aim: To investigate the genotype frequencies of MLH1 promoter polymorphism -93G>A and to determine whether it could play any role in modulating familial and sporadic CRC susceptibility risk. Methods: A case-control study comprising of 104 histopathologically confirmed CRC patients as cases (52 sporadic CRC and 52 Lynch syndrome patients) and 104 normal healthy individuals as controls was undertaken. DNA was extracted from peripheral blood and the polymorphism was genotyped employing PCR-RFLP methods. The genotypes were categorized into homozygous wild type, heterozygous and homozygous variants. The risk association between these polymorphisms and CRC susceptibility risk was calculated using binary logistic regression analysis and deriving odds ratios (ORs). Results: When risk association was investigated for all CRC patients as a single group, the heterozygous (G/A) genotype showed a significantly higher risk for CRC susceptibility with an OR of 2.273, (95%CI: 1.133-4.558 and p-value=0.021). When analyzed specifically for the 2 types of CRC, the heterozygous (G/A) genotype showed significantly higher risk for sporadic CRC susceptibility with and OR of 3.714, (95%CI: 1.416-9.740 and p-value=0.008). Despite high OR value was observed for Lynch syndrome (OR: 1.600, 95%CI: 0.715-3.581), the risk was not statistically significant (P=0.253). Conclusion: Our results suggest an influence of MLH1 promoter polymorphism -93G>A in modulating susceptibility risk in Malaysian CRC patients, especially those with sporadic disease.