BIRC5 and cancer: Several studies have reported a greater efficacy in the therapeutic application of siRNA against malignant tumors in combination with other chemotherapeutic agents, such as with gemcitabine together with ribonucleotide reductase-siRNA (Duxbury et al., 2004), CPT together with WRN helicase-siRNA (Futami et al., 2007) and Adriamycin together with survivin-siRNA (Yonesaka et al., 2006).