title: Endothelial nitric oxide synthase gene polymorphism in gastric cancer.
abstract: OBJECTIVE
  Nitric oxide, a labile compound synthesized by nitric oxide synthase, is a major regulator not only of physiological vascular tonus but also of the abnormal vascularity associated with tumors. Endothelial production of nitric oxide regulates blood flow and angiogenesis and reduces tumor cell adhesion to the endothelium. A high concentration of nitric oxide and its metabolites causes DNA damage during nitration, nitrosation and deamination. Both positive and negative effects on carcinogenesis and tumor growth, apoptosis, and cytotoxic mechanisms may be explained by differential susceptibility of tumor cells to nitric oxide-mediated reactions.
  
  
  METHODS
  In this study, three major polymorphisms (786T>C, the 27 base pair variable number of tandem repeats in intron 4, and 894G>T) of the endothelial nitric oxide synthase gene were investigated in gastric cancer and normal tissues of 50 patients with gastric cancer and in the peripheral blood of 98 healthy subjects.
  
  
  RESULTS
  We found no significant differences in intron 4a/b and 894G>T (Glu298Asp) allele and genotype frequencies between control and patient specimens. Nevertheless, the genotype and allele frequencies of 786T>C polymorphism were found to be significantly different between the healthy controls and tumor tissues.
  
  
  CONCLUSIONS
  The results suggest that endothelial nitric oxide synthase 786T>C polymorphism may play a role in the development of gastric cancer.
authors.affiliation: Department of Pharmacology, Başkent University, School of Medicine, Ankara. mugetecder@yahoo.com
authors.forename: Müge
authors.initials: M
authors.lastname: Tecder Ünal
authors.forename: Halil G
authors.initials: HG
authors.lastname: Karabulut
authors.forename: Güvem
authors.initials: G
authors.lastname: Gümüş-Akay
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Dölen
authors.forename: Atilla
authors.initials: A
authors.lastname: Elhan
authors.forename: Ajlan
authors.initials: A
authors.lastname: Tükün
authors.forename: Ali Ekrem
authors.initials: AE
authors.lastname: Ünal
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D011110:Polymorphism, Genetic; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism
chemical_list: D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III