title: Blood leukocyte DNA hypomethylation and gastric cancer risk in a high-risk Polish population.
abstract: Global hypomethylation has been shown to increase genome instability potentially leading to increased cancer risk. We determined whether global methylation in blood leukocyte DNA was associated with gastric cancer in a population-based study on 302 gastric cancer cases and 421 age- and sex-matched controls in Warsaw, Poland, between 1994 and 1996. Using PCR-pyrosequencing, we analyzed methylation levels of Alu and LINE-1, 2 CG-rich repetitive elements, to measure global methylation levels. Gastric cancer risk was highest among those with lowest level of methylation in either Alu (OR = 1.3, 95% CI = 0.9-1.9) or LINE-1 (OR = 1.4, 95% CI = 0.9-2.0) relative to those with the highest levels, although the trends were not statistically significant. For Alu, the association was stronger among those aged 70 or older (OR = 2.6, 95% CI = 1.3-5.5, p for interaction = 0.02). We did not observe meaningful differences in the associations by other risk factors and polymorphisms examined. For LINE-1, the association tended to be stronger among individuals with a family history of cancer (OR = 3.1, 95% CI = 1.4-7.0, p for interaction = 0.01), current alcohol drinkers (OR = 1.9, 95% CI = 1.0-3.6, p for interaction = 0.05), current smokers (OR = 2.3, 95% CI = 1.1-4.6, p for interaction = 0.02), those who rarely or never consumed fruit (OR = 3.1, 95% CI = 1.2-8.1, p for interaction = 0.03), CC carriers for the MTRR Ex5+123C>T polymorphism (OR = 2.3, 95% CI = 1.2-4.4, p for interaction = 0.01) and TT carriers for the MTRR Ex15+572T>C polymorphism (OR = 1.7, 95% CI = 1.0-2.8, p for interaction = 0.06). The association was not different by sex, Helicobacter pylori infection, intake of folate, vitamin B6 and total protein and the remaining polymorphisms examined. Our results indicate that interactions between blood leukocyte DNA hypomethylation and host characteristics may determine gastric cancer risk.
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. l-hou@northwestern.edu
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Samantha
authors.initials: S
authors.lastname: Sartori
authors.forename: Andrew
authors.initials: A
authors.lastname: Gawron
authors.forename: Jolanta
authors.initials: J
authors.lastname: Lissowska
authors.forename: Valentina
authors.initials: V
authors.lastname: Bollati
authors.forename: Letizia
authors.initials: L
authors.lastname: Tarantini
authors.forename: Fang Fang
authors.initials: FF
authors.lastname: Zhang
authors.forename: Witold
authors.initials: W
authors.lastname: Zatonski
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Andrea
authors.initials: A
authors.lastname: Baccarelli
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007962:Leukocytes / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011044:Poland; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D055815:Young Adult
chemical_list: D004273:DNA, Neoplasm