title: Polymorphisms in methionine synthase (A2756G) and cystathionine beta-synthase (844ins68) and susceptibility to carcinomas of the upper gastrointestinal tract.
abstract: OBJECTIVE
  Folate deficiency is considered to increase the risk for the development of malignant tumors such as prostate and colorectal cancer. Methionine synthase (MTR) and cystathionine ss-synthase (CBS) are enzymes that play a central role in folate metabolism, thereby affecting DNA methylation and synthesis. A single A-->G substitution at nucleotide 2756 of the MTR and a 68 bp CBS insertion polymorphism in exon 8 have been associated with decreased enzyme activity. The purpose of this study is to compare the association of the MTR A2756G polymorphism and CBS insertion polymorphism with susceptibility to carcinomas of the upper gastrointestinal tract.
  
  
  METHODS
  Using the restriction fragment length polymorphism (RFLP)-PCR, the prevalence of MTR A2756G and CBS insertion polymorphism was determined in healthy controls (n = 257) and in patients with esophageal squamous cell carcinoma (ESCC) (n = 263), Barrett's esophagus-associated esophageal adenocarcinoma (BC) (n = 89), cardiac carcinoma (CC) (n = 144), or gastric carcinoma (GC) (n = 221) from German Caucasian subjects.
  
  
  RESULTS
  No significant difference in MTR A2756G genotype distribution was observed between controls (A/A 66.9%, A/G 29.8%, G/G 3.3%) and patients with ESCC (A/A 61.7%, A/G 36.3%, G/G 2.1%), BC (A/A 69.2%, A/G 26.9%, G/G 3.9%), CC (A/A 51.8%, A/G 44.6%, G/G 3.6%), or GC (A/A 73.4%, A/G 20.9%, G/G 5.7%). Similarly, the CBS genotype (I: allele with 68 bp insertion; N: allele without insertion) distribution among German patients with ESCC (N/N 86.8%, I/N 13.2%), BC (N/N 90.2%, I/N 9.8%), CC (N/N 90.1%, I/N 9.9%) or GC (N/N 91.3%, I/N 8.7%) was not different from healthy controls (N/N 90.4%, I/N 9.6%). The gene allele constellation I/I was not present.
  
  
  CONCLUSIONS
  The current study suggests that there is no association between MTR A2756G polymorphism and the CBS (844ins68) insertion polymorphism and cancer of the upper gastrointestinal tract.
authors.affiliation: Department of Pathology, Unfallkrankenhaus Berlin, Warener Strasse 7, 12683 Berlin, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Ott
authors.forename: H
authors.initials: H
authors.lastname: Geddert
authors.forename: M
authors.initials: M
authors.lastname: Sarbia
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000235:genetics*; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics; D016022:Case-Control Studies; D015331:Cohort Studies; D003541:Cystathionine beta-Synthase / Q000235:genetics*; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide
chemical_list: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D003541:Cystathionine beta-Synthase