Investigation of the role of 8-OHdG and oxidative stress in papillary thyroid carcinoma

The aim of this study was to determine levels of serum 8-hydroxy-2'-deoxyguanosine (8-OHdG) as an indicator of oxidant-induced DNA damage and oxidant status in patients with papillary thyroid carcinoma before and after surgery. This study included 25 patients with papillary thyroid carcinoma and age-matched 27 healthy controls. Total antioxidant status (TAS), total oxidant status (TOS), lipid hydroperoxide (LOOH), and 8-OHdG levels were measured. 8-OHdG levels were significantly higher in the preoperative papillary thyroid carcinoma (PTC) group compared with the healthy control group (p<0.001) and were significantly lower after operation in patients with papillary thyroid carcinoma (p=0.004). Oxidative stress index (OSI) levels were significantly higher in both preoperative and postoperative PTC patients compared with the healthy control group (p<0.001 and p<0.001, respectively). TOS levels were higher in the preoperative and postoperative PTC groups compared to the healthy control group (p<0.001 and p<0.001, respectively). TAS levels was lower in the preoperative PTC groups compared to the healthy control group (p=0.011). Serum LOOH levels were higher in both preoperative and postoperative PTC groups compared to the healthy control group (p<0.001 and p<0.001, respectively). Correlation analysis yielded that serum 8-OHdG levels were positively correlated with OSI and LOOH levels in patients with PTC before surgery (r=0.668, p<0.001; r=0.446, p=0.025, respectively) and had a negative correlation with TAS levels (r=-0.616, p=0.001). We have shown severe oxidative DNA damage and impaired antioxidant status in papillary thyroid carcinoma.