title: Biochemical changes in tumor tissues of oral cancer patients.
abstract: OBJECTIVE
  Our aim was to assess the oxidative stress in tumor tissues of oral cancer patients by measuring the levels of lipids, thiobarbituric acid reactive substances (TBARS) and antioxidants.
  
  
  METHODS
  This study has been conducted on oral tumor tissues of 48 adult male oral cancer patients with various clinical stages (stage II to stage IV; 16 of each) and normal tissues of an equal number of age and sex matched disease free healthy subjects. The levels of lipids, lipid peroxidation and antioxidants in buccal mucosa of healthy subjects and oral cancer patients were assayed using colorimetric methods, except for vitamin E (fluorometriy).
  
  
  RESULTS
  Total cholesterol and esterified cholesterol were markedly increased whereas phospholipids and free fatty acids were significantly decreased in tumor tissues as compared to normal tissues. The decrease in TBARS levels and functional compromise of antioxidant defense mechanisms were observed in the tumor tissues as compared to normal subjects.
  
  
  CONCLUSIONS
  The low availability of peroxidizable substrates and the enhanced antioxidant capacity in tumor tissues make them less susceptible to oxidative stress, conferring a selective growth advantage on tumor cells.
authors.affiliation: Department of Biochemistry, Annamalai University, Annamalainagar-608 002, Tamil Nadu, India.
authors.forename: K
authors.initials: K
authors.lastname: Kolanjiappan
authors.forename: C R
authors.initials: CR
authors.lastname: Ramachandran
authors.forename: S
authors.initials: S
authors.lastname: Manoharan
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D016022:Case-Control Studies; D002374:Catalase / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation; D008297:Male; D009061:Mouth Mucosa / Q000378:metabolism; D009062:Mouth Neoplasms / Q000378:metabolism*; D009369:Neoplasms / Q000378:metabolism; D018384:Oxidative Stress; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism*; D014810:Vitamin E / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005230:Fatty Acids, Nonesterified; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D002784:Cholesterol; D002374:Catalase; D005978:Glutathione