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 analyzed 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 polyclonal 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.