title: Absence of the DNA repair enzyme human 8-oxoguanine glycosylase is associated with an aggressive breast cancer phenotype.
abstract: BACKGROUND
  8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is the most abundant marker of DNA damage and it reflects oxidative stress. Human 8-oxoguanine glycosylase (hOGG1) is a DNA-repair enzyme that participates in 8-oxodG removal.
  
  
  METHODS
  hOGG1 protein expression was immunohistochemically studied in 96 patients with local or locally advanced breast cancer and in 20 lesions of non-malignant breast disease. 8-OxodG levels had been previously determined in all patients.
  
  
  RESULTS
  hOGG1 was overexpressed in invasive vs non-invasive lesions (P=0.006). 8-OxodG and hOGG1 had a significant inverse association (P=0.046). Lack of hOGG1 expression was associated with the most poor prognostic factors of breast cancer. In addition, all triple-negative breast carcinomas (TNBCs) were hOGG1 negative (P=0.027 vs non-TNBCs). Patients with a lack of both hOGG1- and 8-oxodG immunostaining showed extremely poor breast cancer-specific survival compared with those with either 8-oxodG- or hOGG1-positive tumours (P<0.000005).
  
  
  CONCLUSIONS
  The current results imply that absence of hOGG1 expression is associated with features of aggressive breast cancer. Tumours lacking both 8-oxodG and hOGG1 seem to indicate especially poor prognosis.
authors: Department of Oncology and Radiotherapy, Oulu University Hospital and University of Oulu, PO Box 22, FIN-90029, Oulu, Finland. peeter.karihtala@oulu.fi
authors: P
authors: P
authors: Karihtala
authors: S
authors: S
authors: Kauppila
authors: U
authors: U
authors: Puistola
authors: A
authors: A
authors: Jukkola-Vuorinen
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology*; D045647:DNA Glycosylases / Q000378:metabolism*; D004260:DNA Repair; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D010641:Phenotype
chemical_list: D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human