title: Methylenetetrahydrofolate reductase polymorphisms and risk of sporadic and hereditary colorectal cancer with or without microsatellite instability.
abstract: Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in the folate metabolism, which affects DNA synthesis and methylation. Low enzyme activity may reduce the capacity of DNA methylation, and possibly reduce uracil misincorporation into DNA, which can result in double strand breaks. Both processes may be critical for the oncogenic transformation of human cells. Two common amino acid-changing and enzyme activity-reducing nucleotide polymorphisms (677C --> T/Ala222Val and 1298A --> C/Glu428Ala) have been described in MTHFR. We performed estimations of the relative risk associated with these two polymorphisms in samples from 287 colorectal cancer patients, compared to 346 healthy controls. Relative risk were further determined for subpopulations of cancer patients having sporadic (n = 227) or suspected/verified hereditary disease (n = 60) and tumours exhibiting high-level microsatellite instability (n = 41) or not (n = 246). No significant differences for the relative risk of colorectal cancer were observed for the MTHFR genotypes either alone or in combination in the analysed cohorts, although the frequency of the 1298AA + AC genotypes was increased among the 60 cases with hereditary disease. Whereas our results do not support an association of high enzyme activity and increased risk of colorectal cancer in general, we can not exclude an association of patients with hereditary disease and the MTHFR 1298A --> C variant.
authors.affiliation: Department of Surgical Research, Carl Gustav Carus Hospital, Dresden University of Technology, Fetscherstrasse 74, D-01307 Dresden, Germany. plaschke@rcs.urz.tu-dresden.de
authors.forename: Jens
authors.initials: J
authors.lastname: Plaschke
authors.forename: Uta
authors.initials: U
authors.lastname: Schwanebeck
authors.forename: Steffen
authors.initials: S
authors.lastname: Pistorius
authors.forename: Hans D
authors.initials: HD
authors.lastname: Saeger
authors.forename: Hans K
authors.initials: HK
authors.lastname: Schackert
mesh_terms: D000236:Adenoma / Q000235:genetics*; D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D019175:DNA Methylation; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D018895:Microsatellite Repeats; D008875:Middle Aged; D016017:Odds Ratio; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)