Increased in 8-oxodG levels in kidney tumors. DNA was extracted from normal kidney and kidney tumor from patients with tuberous sclerosis. Detection of dG and 8-oxodG was performed by HPLC-EC analysis. Authentic standards of 8-oxodG and dG were analyzed simultaneously. Standard curves for dG and 8-oxodG were prepared and quantitated by linear regression analyses Histograms represent means ± SE normal kidney samples and kidney tumors from patients with tuberous sclerosis. Significant difference between control and tumor groups is indicated by **P < 0.01.