title: Methionine synthase D919G polymorphism, folate metabolism, and colorectal adenoma risk.
abstract: Methionine synthase [5-methyltetrahydrofolate-homocysteine S-methyltransferase (MTR)] is involved in folate-mediated one-carbon metabolism, a pathway known to play a role in colorectal carcinogenesis. We investigated whether the MTR D919G polymorphism was associated with risk of colorectal adenoma in a colonoscopy-based study of 513 cases and 609 controls from Minneapolis, MN. Adenoma risk appeared nonsignificantly increased among women with DG or GG genotype [adjusted odds ratio (OR) versus DD, 1.4; 95% confidence interval (CI), 0.9-2.1] but not men (OR, 1.0; 95% CI, 0.7-1.5). An interaction with methionine intake was observed among women, such that low versus high intake was associated with a 2.3-fold increased risk only among those with DG or GG genotype (95% CI, 1.1-4.9; P for interaction = 0.05). Similarly, risk associated with alcohol intake was not elevated among women with the DD genotype; however, consumption of >7 g of alcohol/day versus none was associated with an increased risk among women with DG or GG genotype (adjusted OR, 2.5; 95% CI, 1.4-4.4; P for interaction = 0.03). An interaction between MTR D919G and the thymidylate synthase (TS or TYMS) 3'-untranslated region polymorphism 1494del6 was also observed among women (P for interaction = 0.007). No evidence of interaction with intake of folate, vitamin B(12), or vitamin B(6) or with genotype at MTHFR C677T or the TS enhancer region 28-bp repeat polymorphism was seen. These findings add to what is known about the complexities of genetic variations in one-carbon-metabolizing enzymes in relation to colorectal carcinogenesis.
authors.affiliation: Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Goode
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.forename: Jeannette
authors.initials: J
authors.lastname: Bigler
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000235:genetics*; D000236:Adenoma / Q000235:genetics*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000378:metabolism*; D005838:Genotype; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D011110:Polymorphism, Genetic; D012307:Risk Factors; D017678:Sex Distribution
chemical_list: D005492:Folic Acid; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase