title: Prospective study of urinary prostaglandin E2 metabolite and colorectal cancer risk.
abstract: OBJECTIVE
  Overexpression of cyclooxygenase-2 (COX-2) has been shown to play a major role in colorectal cancer pathogenesis. However, no human study has directly investigated whether biomarkers of COX-2 overexpression may predict colorectal cancer risk. We evaluated the association of urinary prostaglandin E2 metabolite (PGE-M) levels and colorectal cancer risk.
  
  
  METHODS
  A nested case-control study was conducted within the Shanghai Women's Health Study, in which 74,942 Chinese women ages 40 to 70 years were recruited from 1997 to 2000. Urinary PGE-M in 150 cohort members who developed colorectal cancer during the follow-up were compared with 150 matched controls.
  
  
  RESULTS
  The baseline level of urinary PGE-M was more than 50% higher in cases than in controls. The relative risks (RRs) of developing colorectal cancer were elevated from 1.0 to 2.5 (95% CI, 1.1 to 5.8), 4.5 (95% CI, 1.9 to 10.9), and 5.6 (95% CI, 2.4 to 13.5) with increasing quartiles of urinary PGE-M levels (P for trend < .001). The positive association was observed for both colon cancer (RR = 4.9; 95% CI, 1.7 to 14.7 for the highest v lowest quartile; P for trend = .009) and rectal cancer (RR = 7.2; 95% CI, 1.7 to 30.7; P for trend = .048), and for colorectal cancer cases diagnosed in the first 30 months (RR = 7.6; 95% CI, 1.8 to 32.0; P for trend = .035) and subsequent months (RR = 4.4, 95% CI, 1.5 to 13.3; P for trend = .012) of follow-up.
  
  
  CONCLUSIONS
  Given its strong association with colorectal cancer risk, urinary PGE-M may be a promising biomarker for risk assessment of this common malignancy.
authors.affiliation: Department of Medicine, Center for Epidemiology Research, and Vanderbilt-Ingram Cancer Center, Nashville, TN, USA.
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Gong
authors.initials: G
authors.lastname: Yang
authors.forename: Bu-Tian
authors.initials: BT
authors.lastname: Ji
authors.forename: Wanqing
authors.initials: W
authors.lastname: Wen
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Rothman
authors.forename: Hong-Lan
authors.initials: HL
authors.lastname: Li
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000652:urine*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000652:urine*; D015232:Dinoprostone / Q000652:urine*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor; D015232:Dinoprostone