Peroxiredoxins in breast carcinoma.
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.
Karihtala
Peeter
P
Department of Pathology, University of Oulu and Oulu University Hospital, 90014 Oulu, Finland.
Mäntyniemi
Anne
A
Kang
Sang Won
SW
Kinnula
Vuokko L
VL
Soini
Ylermi
Y
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
D000975:Antioxidants; D020033:Protein Isoforms; D017382:Reactive Oxygen Species; D011980:Receptors, Progesterone; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins