Browsing by Subject "Polymorphism, Genetic"

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    DNA repair gene polymorphisms and bladder cancer susceptibility in a Turkish population
    (International Institute of Anticancer Research, 2006) Karahalil, B.; Kocabas, N. A.; Özçelik, T.
    Background: Occupational exposure and life style preferences, such as smoking are the main known environmental susceptibility factors for bladder cancer. A growing list of chemicals has been shown to induce oxidative DNA damage. Base excision repair (BER) genes (X-ray repair cross complementing 1, XRCC1 and human 8-oxoguanine DNA glycosylase 1, OGG1) may play a key role in maintaining genome integrity and preventing cancer development. Materials and Methods: We tested whether polymorphisms in XRCC1 and OGG1 are associated with bladder cancer risk by using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay. In addition, the possible modifying affect of cigarette smoking was evaluated. Results: No studies, to date, have examined the association between genetic polymorphisms in DNA repair genes and bladder cancer susceptibility, in the Turkish population. We found the OGG1 Cys326Cys genotype to be more frequent among bladder cancer patients (odds ratio (OR): 2.41 (95% CI, 1.36-4.25)). However, in the case of XRCC1, there was no significant difference in susceptibility to bladder cancer development between patients with the Arg399 and these with the Gln399 allele (OR: 0.72 (95% CI, 0.41-1.26)). Conclusion: Our data showed that OGG1 genetic polymorphisms might be useful as prognostic genetic markers for bladder cancer in the clinical setting.
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    Extremely skewed X-chromosome inactivation patterns in women with recurrent spontaneous abortion
    (Wiley-Blackwell Publishing Asia, 2006) Bagislar, S.; Ustuner, I.; Cengiz, B.; Soylemez, F.; Akyerli, C. B.; Ceylaner, S.; Ceylaner, G.; Acar, A.; Ozcelik, T.
    Background: The role of extremely skewed X-chromosome inactivation (XCI) has been questioned in the pathogenesis of recurrent spontaneous abortion (RSA) but the results obtained were conflicting. Aims: We therefore investigated the XCI patterns in peripheral blood DNA obtained from 80 patients who had RSA and 160 age-matched controls. Methods: Pregnancy history, age, karyotype, and disease information was collected from all subjects. The methylation status of a highly polymorphic cytosine-adenine-guanine repeat in the androgen-receptor (AR) gene was determined by use of methylation-sensitive restriction enzyme HpaII and polymerase chain reaction. Results: Skewed XCI (> 8 5% skewing) was observed in 13 of the 62 patients informative for the AR polymorphism (20.9%), and eight of the 124 informative controls (6.4%) (P = 0.0069; χ 2 test). More importantly, extremely skewed XCI, defined as > 90% inactivation of one allele, was present in 11 (17.7%) patients, and in only two controls (P = 0.0002; χ 2 test). Conclusions: These results support the interpretation that disturbances in XCI mosaicism may be involved in the pathogenesis of RSA.
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    Polymorphisms of glutathione S-transferase genes (GSTM1, GSTP1 and GSTT1) and bladder cancer susceptibility in the Turkish population
    (Springer, 2001) Törüner, G. A.; Akyerli, C.; Uçar, A.; Aki, T.; Atsu, N.; Özen, H.; Tez, M.; Çetinkaya, M.; Özçelik, T.
    We investigated the effect of the GSTM1 and GSTT1 null genotypes, and GSTP1 313 A/G polymorphism on bladder cancer susceptibility in a case control study of 121 bladder cancer patients, and 121 age- and sex-matched controls of the Turkish population. The adjusted odds ratio for age, sex, and smoking status is 1.94 [95% confidence intervals (CI) 1.15-3.26] for the GSTM1 null genotype, and 1.75 (95% CI 1.03-2.99) for the GSTP1 313 A/G or G/G genotypes. GSTT1 was shown not to be associated with bladder cancer. Combination of the two high-risk genotypes, GSTM1 null and GSTP1 313 A/G or G/G, revealed that the risk increases to 3.91-fold (95% CI 1.88-8.13) compared with the combination of the low-risk genotypes of these loci. In individuals with the combined risk factors of cigarette smoking and the GSTM1 null genotype, the risk of bladder cancer is 2.81 times (95% CI 1.23-6.35) that of persons who both carry the GSTMl-present genotype and do not smoke. Similarly, the risk is 2.38-fold (95% CI 1.12-4.95) for the combined GSTP1 313 A/G and G/G genotypes and smoking. These findings support the role for the GSTM1 null and the GSTP1 313 AG or GG genotypes in the development of bladder cancer. Furthermore, gene-gene (GSTM1-GSTP1) and gene-environment (GSTMl-smoking, GSTP1-smoking) interactions increase this risk substantially.