title: High homocysteine is associated with increased risk of colorectal cancer independently of oxidative stress and antioxidant capacities.
abstract: OBJECTIVE
  Increased homocysteine concentration and oxidative stress and decreased antioxidant capacities are thought to affect carcinogenesis. However, the associations of homocysteine, cysteine, pyridoxal 5'-phosphate (PLP) and folate with oxidative stress and antioxidant capacities in patients with colorectal cancer are unclear. The purpose of this study was to determine the associations of homocysteine, cysteine, PLP and folate with oxidative stress indicators and antioxidant capacities, and to further analyze their relationships with respect to risk for colorectal cancer.
  
  
  METHODS
  One hundred and sixty-eight subjects with colorectal cancer (cases) and 188 healthy subjects (controls) were recruited.
  
  
  RESULTS
  There were no significant associations of homocysteine, cysteine and folate with oxidative stress indicators and antioxidant capacities in cases; however, PLP positively correlated with glutathione S-transferase activities after adjusting for potential confounders in cases. Subjects with higher plasma homocysteine concentration exhibited significantly increased risk of colorectal cancer with or without adjustment for potential confounders. The associations of cysteine, PLP and folate with the risk of colorectal cancer were not observed when potential confounders were adjusted.
  
  
  CONCLUSIONS
  Increased homocysteine was strongly associated with the risk of colorectal cancer independently of oxidative stress indicators and antioxidant capacities. However, cysteine, PLP and folate were not found to be related to oxidative stress, antioxidant capacities and the risk of colorectal cancer.
authors.affiliation: Division of Colorectal Surgery, Department of Surgery, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Feng-Fan
authors.initials: FF
authors.lastname: Chiang
authors.affiliation: Division of Colorectal Surgery, Department of Surgery, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Hwei-Ming
authors.initials: HM
authors.lastname: Wang
authors.affiliation: School of Nutrition, Chung Shan Medical University, Taichung, Taiwan; Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Lan
authors.affiliation: School of Nutrition, Chung Shan Medical University, Taichung, Taiwan; Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Min-Hsiu
authors.initials: MH
authors.lastname: Yang
authors.affiliation: Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
authors.forename: Shih-Chien
authors.initials: SC
authors.lastname: Huang
authors.affiliation: School of Nutrition, Chung Shan Medical University, Taichung, Taiwan; Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan. Electronic address: ych@csmu.edu.tw.
authors.forename: Yi-Chia
authors.initials: YC
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D015992:Body Mass Index; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood / Q000453:epidemiology*; D003404:Creatinine / Q000097:blood; D003545:Cysteine / Q000097:blood; D005260:Female; D005492:Folic Acid / Q000097:blood; D005979:Glutathione Peroxidase / Q000097:blood; D005982:Glutathione Transferase / Q000097:blood; D064368:Healthy Volunteers; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D011732:Pyridoxal Phosphate / Q000097:blood; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D000975:Antioxidants; D012709:Serum Albumin; D006710:Homocysteine; D011732:Pyridoxal Phosphate; D005492:Folic Acid; D003404:Creatinine; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D003545:Cysteine
keywords: Antioxidant capacities; Colorectal cancer; Cysteine; Homocysteine; Oxidative stress; Pyridoxal 5′-phosphate