title: Peroxiredoxins in breast carcinoma.
abstract: OBJECTIVE
  Peroxiredoxins (Prxs) are a novel group of peroxidases containing high antioxidant efficiency and some of them having also effects on cell differentiation and apoptosis. The mammalian Prx family has six distinct members located in various subcellular locations, including peroxisomes and mitochondria, places where oxidative stress is most evident.
  
  
  METHODS
  We examined immunohistochemically a large set of samples from patients with breast carcinoma and investigated associations with parameters such as tumor-node-metastasis classification, hormone receptor status, and patient survival. Three biopsies of healthy breast tissue were used as controls.
  
  
  RESULTS
  Expression of peroxiredoxins I, III, IV, and V was found in >or=80% of cases, whereas the expression of Prx II and VI was less frequent. Increased expression of Prx III was found to associate with the presence of progesterone (P = 0.02) and estrogen (P = 0.03) receptors, and Prxs IV (P = 0.009) and VI (P = 0.04) were overexpressed in progesterone receptor positive cases. Prx V was the only isoform that associated with items of tumor-node-metastasis classification, it was connected to a larger tumor size (P = 0.05) and positive lymph node status (P = 0.04). Prx V positivity was also connected with shorter survival (P = 0.04), whereas Prxs III (P = 0.002) and IV (P = 0.02) were related to better prognosis, probably resulting from their connection with a positive hormone receptor status.
  
  
  CONCLUSIONS
  In conclusion, we found that expression of peroxiredoxins, especially III, IV and V, is increased in breast malignancy, suggesting the induction of Prxs as response to increased production of reactive oxygen species in carcinomatous tissue.
authors.affiliation: Department of Pathology, University of Oulu and Oulu University Hospital, 90014 Oulu, Finland.
authors.forename: Peeter
authors.initials: P
authors.lastname: Karihtala
authors.forename: Anne
authors.initials: A
authors.lastname: Mäntyniemi
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Kang
authors.forename: Vuokko L
authors.initials: VL
authors.lastname: Kinnula
authors.forename: Ylermi
authors.initials: Y
authors.lastname: Soini
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism; D002454:Cell Differentiation; D002455:Cell Division; D002470:Cell Survival; D006801:Humans; D007150:Immunohistochemistry; D009362:Neoplasm Metastasis; D010544:Peroxidases / Q000096:biosynthesis*; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D020033:Protein Isoforms; D017382:Reactive Oxygen Species; D011980:Receptors, Progesterone / Q000096:biosynthesis; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000975:Antioxidants; D020033:Protein Isoforms; D017382:Reactive Oxygen Species; D011980:Receptors, Progesterone; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins