title: Oxidative DNA damage and β-catenin expression in colorectal cancer evolution.
abstract: OBJECTIVE
  Oxidative DNA damage is one of the mechanisms associated to initial colorectal carcinogenesis, but how it interacts with β-catenin, an adherence protein related to cancer evolution, is not clear. This study investigates the relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colon tumor tissue (adenoma and adenocarcinoma) in colorectal adenocarcinoma evolution.
  
  
  METHODS
  One hundred and 13 samples were studied. Hematoxylin-eosin determined histological grade. β-Catenin expression was analyzed by immunohistochemistry. The oxidative DNA damage was evaluated using comet assay technique. The coefficient for rejection of the nullity hypothesis was taken to 5 %. Kruskal-Wallis, Spearman test, and partial correlation were used to analyze the data.
  
  
  RESULTS
  There was oxidative DNA damage increase in colorectal cancer evolution (p < 0.01). Histological grade was correlated with oxidative DNA damage (p < 0.01). There were differences in β-catenin expression among normal, adenoma, and adenocarcinoma tissue with progressive increase of β-catenin expression (p < 0.00). Histological grade was correlated to β-catenin expression (p < 0.00). There was a relationship (p < 0.00) between β-catenin and histological grade while controlling for the effect of oxidative DNA damage.
  
  
  CONCLUSIONS
  The findings of this study make it possible to establish a relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colorectal tumor tissue. Additionally, they show a causal relationship between variations of β-catenin in different tissues analyzed while controlling for the effect of oxidative DNA damage.
authors.affiliation: Postgraduate Program Strictu Senso in Health Science, Sao Francisco University Medical School, Sao Paulo, Brazil. depriolli@terra.com.br
authors.forename: Denise G
authors.initials: DG
authors.lastname: Priolli
authors.forename: Thamy P
authors.initials: TP
authors.lastname: Canelloi
authors.forename: Camila O
authors.initials: CO
authors.lastname: Lopes
authors.forename: Júlio C M
authors.initials: JC
authors.lastname: Valdívia
authors.forename: Natalia P
authors.initials: NP
authors.lastname: Martinez
authors.forename: Demetrius P
authors.initials: DP
authors.lastname: Açari
authors.forename: Izilda A
authors.initials: IA
authors.lastname: Cardinalli
authors.forename: Marcelo L
authors.initials: ML
authors.lastname: Ribeiro
mesh_terms: D003106:Colon / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D004249:DNA Damage; D018450:Disease Progression; D006801:Humans; D008875:Middle Aged; D018384:Oxidative Stress; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D051176:beta Catenin
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