Association of DNA methyltransferases 3A and 3B polymorphisms, and plasma folate levels with the risk of urothelial carcinoma

• Published in: PloS one 2014-08, Vol.9 (8), p.e104968
• Main Authors: Chung, Chi-Jung, Chang, Chao-Hsiang, Liu, Chiu-Shong, Huang, Chi-Ping, Chang, Yi-Huei, Chien, Ssu-Ning, Tsai, Ping-Huan, Hsieh, Hui-An
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Biology and Life Sciences; Bladder cancer; Carcinogenesis; Carcinogens; Case-Control Studies; Cigarette smoking; Confidence intervals; Control methods; Deoxyribonucleic acid; DNA; DNA (Cytosine-5-)-Methyltransferases - genetics; DNA methylation; DNA Methyltransferase 3A; DNA Methyltransferase 3B; Ecological risk assessment; Environmental factors; Epigenetics; Female; Folic acid; Folic Acid - blood; Gene-Environment Interaction; Genetic diversity; Genetic Predisposition to Disease; Genotyping; Health risk assessment; Humans; Immunoassay; Male; Medicine and Health Sciences; Metabolism; Middle Aged; Patients; Polymerase chain reaction; Polymorphism; Polymorphism, Single Nucleotide; Restriction fragment length polymorphism; Risk Factors; Smoking; Smoking - adverse effects; Statistical analysis; Studies; Urologic Neoplasms - blood; Urologic Neoplasms - epidemiology; Urologic Neoplasms - genetics; Urothelial carcinoma
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0104968

Interindividual genetic variations of human DNA methyltransferases (DNMTs), which involve the methyl donor from the folate-related one-carbon metabolism pathway, are hypothesized as a risk factor for urothelial carcinoma (UC). Therefore, we evaluated the role of gene-environment interaction in UC carcinogenesis. A hospital-based case-control study was conducted by recruiting 192 patients with UC and 381 controls. Their plasma folate levels were measured using a competitive immunoassay kit. In addition, DNMT3A -448A>G and DNMT3B -579G>T genotyping was evaluated using a polymerase chain reaction-restriction fragment length polymorphism technique. Multivariate logistic regression and 95% confidence intervals (CIs) were applied to estimate the UC risk. We observed that patients with UC exhibited a higher prevalence rate of folate insufficiency (folate levels ≤6 ng/mL) compared with the controls (35.94% and 18.37%, respectively). Furthermore, folate levels were higher in the prevalent UC patients than in the incident UC patients. However, folate insufficiency was similarly associated with a nearly two-fold increase in the risk of UC regardless of the UC patient group. In addition, the frequencies of the variant alleles for DNMT3A and DNMT3B were 0.80 and 0.92, respectively, and no association was observed with UC risk. However, participants with a variant homozygous genotype of DNMT3B -579G>T and folate insufficiency or with high cumulative cigarette smoking exhibited an increased risk of UC. Overall, environmental factors may contribute more significantly to UC carcinogenesis compared with genetic susceptibility. Future studies should investigate other polymorphisms of DNMT3A and DNMT3B to determine genetic susceptibility.