Overexpression of peroxiredoxin in human breast cancer

The peroxiredoxins (Prx) are a family of 25kDa peroxidases that can reduce H2O2 using an electron from thioredoxin (Trx) or other substances. The mamm alian Prx family is divided into six groups (Prx I-VI) on the basis of homo logy of amino acid sequences. They are located in the cytosol and play a ro le in the cell signaling system. Previous reports have shown that Prx II ha s proliferative and anti-apoptotic properties and thus may induce carcinoge nic changes. We conducted this study to reveal the change in expression of Prx in human breast cancer in comparison to normal tissues. Western immunob lotting using Prx type I, II and III antibodies was undertaken on 24 human breast cancer tissues and normal counterparts. We used antibodies against p urified recombinant NKEF-A/PAG, NKEF-B and MER 5 which are the Prx isoforms . Type I Pix was overexpressed in the cancer tissues of 21 patients (87.5%) , type II in 18 patients (75%) and type III in 19 patients (79.2%) in relat ion to normal tissue. However; no significant relationship was found betwee n Pix overexpression and clinicopathological parameters of breast cancer su ch as tumor size, lymphatic invasiveness, hormone receptor status or nuclea r and histologic grade. In conclusion, Prx is overexpressed in breast cance r tissues to a great extent suggesting that Prx has a proliferative effect and may be related to cancer development or progression.