Interestingly, ARC knockdown sensitised the RCC cells towards topotecan- (Fig. 4b) and ABT263-induced (Fig. 4c) apoptosis by enhancing the activation of the mitochondrial pathway, as determined by caspase-9 and caspase-3 activation as well as mitochondrial depolarisation. The gene discussed is CASP9; the disease is renal cell carcinoma.