Peroxiredoxins and their expression in ependymomas
- Toomas Haapasalo1,
- Kristiina Nordfors1,
- Sally Järvelä1,
- Eloise Kok1,
- Pauli Sallinen1,
- Vuokko L Kinnula2,
- Hannu Kalervo Haapasalo1,
- Ylermi Soini3
- 1Department of Pathology, Fimlab Laboratories, Tampere University Hospital, and University of Tampere, Tampere, Finland
- 2Department of Medicine, Division of Pulmonary Medicine, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
- 3Department of Clinical Pathology and Forensic Medicine, University of Eastern Finland, and Cancer Center of Eastern Finland, Kuopio, Finland
- Correspondence to Dr Hannu Kalervo Haapasalo, Department of Pathology, Tampere University Hospital, P.O. Box 2000, Tampere FIN-33521, Finland;
- Received 5 July 2012
- Revised 5 September 2012
- Accepted 6 September 2012
- Published Online First 16 October 2012
Aims Peroxiredoxins I–VI (Prxs) have recently been shown to have a role in the tumorigenesis of astrocytic brain tumours. In some tumour types they are associated with Nrf2 (transcription factor NF-E2-related factor), a sensor of oxidative stress, and DJ-1 (also known as PARK7), a protein known to stabilise Nrf2.
Methods We investigated the immunohistochemical expression of Prxs I–VI, Nrf2 and DJ-1 in a total of 76 ependymomas and their relationship with clinicopathological features of these tumours.
Results There was a significant expression of all Prxs except Prx IV in the ependymomas. Strong nuclear and cytoplasmic expression of Nrf2 could be detected in these tumours. Prx I expression was significantly associated with cytoplasmic and nuclear Nrf2 expression. Prx I expression was also associated with tumour site, with cerebellar ependymomas having a lower expression of Prx I than other tumours. DJ-1 did not associate with Prxs but nuclear DJ-1 had an inverse association with nuclear Nrf2. Cytoplasmic DJ-1 associated with worse survival in ependymoma patients.
Conclusions This study indicates that oxidative mechanisms as reflected by Nrf2 expression are highly activated in ependymomas. Prxs, especially Prx I, were associated with Nrf2 expression, suggesting a role for Nrf2 in Prx I synthesis in ependymomas. While DJ-1 did not associate with any of the Prxs, its expression was associated with worsened patient survival and could have a role as a prognostic marker in ependymomas.