title: Activity and protein level of CuZnSOD and MnSOD in benign and malignant liver tumors.
abstract: OBJECTIVE
  Superoxide dismutase (SOD) is a key antioxidant enzyme, responsible for scavenging of superoxide anion - a precursor of all reactive oxygen species (ROS). ROS are implicated in many pathologies, particularly in tumor disease. The aim of our work was to evaluate SOD isoforms' activity and protein level changes in liver tumors.
  
  
  METHODS
  Materials were obtained from patients with liver tumors and with liver cirrhosis diagnosed by routine histopathological examination. Activity and protein level of SOD were determined by means of the Beauchamp and Fridovich assay and by Western blot analysis.
  
  
  RESULTS
  Decreased activity of CuZnSOD and MnSOD and distinct differences in SOD isoforms' protein expression in liver cirrhosis were found. Results also showed higher protein level and activity of SOD isoforms in liver malignant tumors than in benign ones.
  
  
  CONCLUSIONS
  Malignant tumors have a better antioxidant system than benign ones. Moreover, weakening of antioxidant mechanisms and accumulation of oxidative damage in cirrhotic liver could initiate liver carcinogenesis.
authors.affiliation: Chair and Department of Biochemistry, Warsaw Medical University, 02-097 Warsaw, Banacha 1, Poland. skryzckimp@poczta.onet.pl
authors.forename: Michał
authors.initials: M
authors.lastname: Skrzycki
authors.forename: Dorota
authors.initials: D
authors.lastname: Scibior
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Podsiad
authors.forename: Hanna
authors.initials: H
authors.lastname: Czeczot
mesh_terms: D018248:Adenoma, Liver Cell / Q000201:enzymology* / Q000378:metabolism; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000201:enzymology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008103:Liver Cirrhosis / Q000201:enzymology / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D011230:Precancerous Conditions / Q000201:enzymology / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D013482:Superoxide Dismutase