title: Urinary 8-hydroxydeoxyguanosine and its analogs as DNA marker of oxidative stress: development of an ELISA and measurement in both bladder and prostate cancers.
abstract: BACKGROUND
  8-hydroxydeoxyguanosine (8-OHdG) is the most frequently detected and studied DNA lesion. Upon DNA repair, 8-OHdG is excreted in the urine. Urinary 8-OHdG is now considered as a biomarker of generalized, cellular oxidative stress and is linked to degenerative diseases including cancer.
  
  
  METHODS
  We developed a competitive enzyme-linked immunosorbent assay (ELISA) for urinary 8-OHdG by coating BSA conjugated 8-hydroxyguanine (8-OHG) on a microplate. Urine specimens containing 8-OHdG and monoclonal anti-8-OHdG antibody were incubated together in the microwell. Final quantification of bound anti-8-OHdG antibody was estimated by the addition of HRP-conjugated sheep-anti-mouse antibody.
  
  
  RESULTS
  The concentration range of the calibration curve was 0-60 ng/ml. The sensitivity of the assay was 0.5 ng/ml. The within-day precision and day-to-day precision were <10%. The ELISA correlated well with a commercial kit (r=0.9). Our assay measured not only 8-OHdG but also 8-OHG and 8-hyroxyguanine in urine. Increased urinary concentration of 8-OHdG and its analogs were detected in both patients with bladder cancer (70.5+/-38.2 ng/mg creatinine) and prostate cancer (58.8+/-43.4 ng/mg creatinine) as compared to the healthy control (36.1+/-24.5 ng/mg creatinine).
  
  
  CONCLUSIONS
  Our preliminary data suggest that the competitive ELISA for 8-OHdG and its analogs appears to be a simple method for quantifying the extent of oxidative stress and may have potential for identifying cancer risk.
authors.affiliation: School of Medical Technology, Chang Gung University, Taoyuan 333, Taiwan.
authors.forename: Chiuan Chian
authors.initials: CC
authors.lastname: Chiou
authors.forename: Pi Yueh
authors.initials: PY
authors.lastname: Chang
authors.forename: Err Cheng
authors.initials: EC
authors.lastname: Chan
authors.forename: Tsu Lan
authors.initials: TL
authors.lastname: Wu
authors.forename: Kuo Chien
authors.initials: KC
authors.lastname: Tsao
authors.forename: James T
authors.initials: JT
authors.lastname: Wu
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D015415:Biomarkers; D002138:Calibration; D002850:Chromatography, Gel; D004247:DNA / Q000737:chemistry*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000652:urine*; D004797:Enzyme-Linked Immunosorbent Assay; D006151:Guanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000652:urine*; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D001749:Urinary Bladder Neoplasms / Q000652:urine*
chemical_list: D015415:Biomarkers; D011933:Reagent Kits, Diagnostic; D006151:Guanosine; C046215:8-hydroxyguanosine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine