title: 5-Lipoxygenase is coexpressed with Cox-2 in sporadic colorectal cancer: a correlation with advanced stage.
abstract: OBJECTIVE
  It has been extensively documented that the cyclooxygenase inducible form and 15-lipoxygenase are implicated in colorectal carcinogenesis. Nonetheless, the role of other enzymes involved in the arachidonic acid metabolism, such as 5-lipoxygenase, in colorectal neoplasms has not been fully ascertained. This study was designed to evaluate 5-lipoxygenase expression in sporadic colorectal adenocarcinomas by using immunohistochemistry and to analyze its potential correlations with clinicopathologic parameters and with cyclooxygenase-2 expression.
  
  
  METHODS
  Expression of 5-lipoxygenase and cyclooxygenase-2 were evaluated by immunohistochemistry in 50 surgically resected sporadic colorectal adenocarcinomas (28 male and 22 female patients age range, 47-88 (mean age, 69 +/- 8) years). The chi-squared and Spearman correlation tests were used to analyze correlations with clinicopathologic characteristics and to evaluate any relationships between expression of the two enzymes. P values <0.05 were considered statistically significant.
  
  
  RESULTS
  5-Lipooxygenase and cyclooxygenase-2 immunostaining was found in the cytoplasm of neoplastic cells in 41 (82 percent) and in 43 cases (86 percent), respectively. Spearman correlation test demonstrated a positive correlation in the expression of the two enzymes. A statistically significant correlation also was observed between 5-lipoxygenase expression and tumor stage and lymph node metastasis, whereas no significant correlations emerged regarding cyclooxygenase-2 expression and clinicopathologic parameters.
  
  
  CONCLUSIONS
  Our study demonstrates that 5-lipoxygenase is expressed in colorectal adenocarcinomas in association with cyclooxygenase-2 expression. Moreover, an elevated expression of this enzyme seems to be significantly correlated with tumor aggressiveness. Further studies would clarify the need for target therapies inhibiting both metabolic pathways in such tumors.
authors.affiliation: Dottorato di Ricerca in Oncologia Clinica, Sperimentale Applicata e Ricerca Translazionale sui Tumori, Università di Messina, Messina, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Barresi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Grosso
authors.forename: Enrica
authors.initials: E
authors.lastname: Vitarelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tuccari
authors.forename: Gaetano
authors.initials: G
authors.lastname: Barresi
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology* / Q000473:pathology* / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology* / Q000601:surgery; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D001094:Arachidonate 5-Lipoxygenase; D051546:Cyclooxygenase 2