CS and renal carcinoma: A total of 14 renal carcinoma tumour tissues, investigated in this study, showed a depletion of the mtDNA content (46%) combined with a decreased activity of complex I (16%), complex II (23%), complex IV (29%), oligomycin-sensitive ATPase activity of complex V (25%) and citrate synthase (72%) compared to matched normal cortex tissues (Table 3) (Meierhofer et al, 2004).