Formation of 8‐hydroxy‐2′‐deoxyguanosine and 4‐hydroxy‐2‐nonenal‐modified proteins in human renal‐cell carcinoma

Abstract

To study the possible involvement of reactive oxygen species (ROS) in the tumor biology of human renal‐cell carcinoma (RCC), we analvzed 35 cases of RCC for 2 parameters of oxidative damage: 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG), a mutation‐prone DNA‐ base ‐modified product, was measured by means of high‐performance liquid chromatography (HPLC) with an electrochemical (EC) detector, and 4‐hydroxy‐2‐nonenal (HNE)‐modified proteins were measured with a poly‐clonal antibody against HNE‐modified proteins. A 54% higher content of 8‐OHdG was found in RCC than in the corresponding non‐tumorous kidney, suggesting that the DNA of RCC is more exposed to ROS than is the DNA of non‐tumorous kidneys. Immunohistochemistry for HNE‐modified proteins showed a distinct staining pattern of fine to coarse granularity in the cytoplasm of RCC (n = 15), implying that lipid peroxidation products are located in cytoplasmic organelles. These results suggest that RCC constitutionally elaborates more ROS than is produced by the non‐tumorous parts of kidneys. No correlation was found between clinical stage, histology, age or sex and the 2 parameters examined.