title: Xanthine oxidoreductase - clinical significance in colorectal cancer and in vitro expression of the protein in human colon cancer cells.
abstract: Xanthine oxidoreductase (XOR) is a key enzyme in degradation of DNA and RNA, and has previously been shown to be decreased in aggressive breast and gastric cancer. In this study, XOR expression was assessed in tissue microarray specimens of 478 patients with colorectal cancer and related to clinical parameters. In addition, we performed in vitro studies of XOR activity, protein and mRNA in colon cancer cells (Caco-2). Results from the tissue expression analyses show that XOR was decreased in 62% and undetectable in 22% of the tumours as compared to normal tissue. Loss of XOR was associated with poor grade of differentiation (p=0.006) and advanced Dukes stage (p=0.03). In multivariate survival analysis, XOR was a prognostic factor (p=0.008), independent of Dukes stage, histological grade, age and tumour location. The in vitro analyses show that XOR is not measurable in undifferentiated Caco-2 cells, but appears and increases with differentiation. We conclude that XOR expression is associated with histological grade of differentiation and extent of disease in colorectal cancer, and it provides significant prognostic information independently of established factors.
authors.affiliation: Department of Oncology, Institute of Clinical Medicine, University of Helsinki, Haartmaninkatu 4, PO Box 105, 00029 Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Linder
authors.forename: Eeva
authors.initials: E
authors.lastname: Martelin
authors.forename: Mikael
authors.initials: M
authors.lastname: Lundin
authors.forename: Johanna
authors.initials: J
authors.lastname: Louhimo
authors.forename: Stig
authors.initials: S
authors.lastname: Nordling
authors.forename: Caj
authors.initials: C
authors.lastname: Haglund
authors.forename: Johan
authors.initials: J
authors.lastname: Lundin
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells / Q000201:enzymology; D002454:Cell Differentiation; D003106:Colon / Q000201:enzymology; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D003593:Cytoplasm / Q000201:enzymology; D005260:Female; D005500:Follow-Up Studies; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D012007:Rectum / Q000201:enzymology; D016019:Survival Analysis; D014968:Xanthine Dehydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D014968:Xanthine Dehydrogenase