Level of selenoprotein transcripts in peripheral leukocytes of patients with bladder cancer and healthy individuals

Background: Low concentrations of selenium (Se) in humans have been associated with risk of cancer. Selenoprotein mRNAs can potentially be regulated by Se status. Methods: Se status, GPx1 Pro198Leu and Sep15 1125G/A genetic polymorphism and human (h)GPx1, hGPx3, hSep15 and hSeP1 transcript levels in peripheral leukocytes of 33 males with bladder cancer and 47 healthy male controls were analysed. Results: All the subjects expressed detectable selenoprotein mRNA concentrations in leukocytes. Significantly lower expression of hGPx1, hGPx3, hSep15 and hSeP1 in leukocytes of bladder cancer patients compared to controls was observed. hGPx1, hGPx3 and hSep15 expression was significantly lower in non-smokers in the control group compared with smokers in the control group. A positive relationship between expression of all studied genes was also observed in non-smoking controls. Expression of hGPx3 and hSep15 gradually increased with tumour grade in patients with cancer. We did not find any association between selenoprotein mRNA levels, Se status and selenoprotein genetic polymorphism. Conclusions: This study showed significant down-regulation of hGPx1, hGPx3, hSep15 and hSeP1 mRNA levels in leukocytes of patients with bladder cancer compared to controls. Selenoprotein transcript levels in circulating leukocytes of patients with bladder cancer and controls revealed no potential impact of Se status on selenoprotein expression. Clin Chem Lab Med 2009;47:1125-32.