Evaluation of dietary factors in relation to the biomarkers of oxidative stress and inflammation in breast cancer risk.

OBJECTIVE

This study was conducted to evaluate blood concentrations of inflammatory cytokines and oxidative stress-related biomarkers as risk factors of breast cancer and to determine the relation between these markers and antioxidant nutrient intake.

METHODS

Study subjects were 134 patients with breast cancer and 149 controls. Total antioxidant capacity and concentrations of 8-isoprostane, 8-hydroxy-2'-deoxyguanosine, interleukin (IL)-1β, IL-6, and IL-8 of blood samples were determined. A food-frequency questionnaire was used to assess nutrient intake.

RESULTS

Patients with breast cancer had significantly higher blood levels of oxidative stress markers compared with control subjects. Plasma concentrations of IL-1β and IL-6 were significantly higher in patients with breast cancer compared with those of control subjects. In the pooled analysis, total antioxidant capacity was significantly decreased with increasing quartiles of carbohydrate intake but was increased with increasing quartiles of total vitamin A intake and vitamin C intake. In addition, 8-hydroxy-2'-deoxyguanosine concentration was decreased with increasing quartiles of vitamin A and β-carotene. No significant association was found between nutrient intake and cytokine concentrations.

CONCLUSIONS

These results suggest that oxidative stress and inflammation may be associated with the risk of breast cancer. Total vitamin A intake was negatively related to oxidative stresses, possibly modifying the risk of breast cancer.