Down-regulation of 8-hydroxydeoxyguanosine and peroxiredoxin II in the pathogenesis of endometriosis-associated ovarian cancer.

Aim: To evaluate the roles of oxidative stress marker 8-hydroxydeoxyguanosine (8-OHdG) and peroxiredoxin (PRX) antioxidants in the development of endometriosis and endometriosis-associated ovarian cancer (EAC). Materials and Methods: Tissue expressions of 8-OHdG, PRX II and PRX IV were determined immunohistochemically in tissue from 22 women with benign endometriosis (BE) and 33 women with EAC, among whom endometriosis and cancer tissues were analyzed separately. Results: When all three groups were compared simultaneously, EAC tumor cells had significantly weaker nuclear 8-OHdG and PRX II expression (p<0.05 and p<0.01, respectively) and significantly weaker cytoplasmic 8-OHdG expression (p<0.01) than EAC endometriosis and BE epithelial cells. This same trend was also observed when groups were compared pair-wise. Conclusion: Nuclear PRX and 8-OHdG were down-regulated in EAC tumorous tissue compared with BE and EAC endometriotic tissue, suggesting a role of oxidative stress in the pathogenesis of EAC.