Serratia marcescens, which belongs to facultative anaerobes, can inhibit the growth of prostate cancer cells by down-regulating IAP family inhibitors XIAP, CIAP-1, and CIAP-2, activating caspase-9 and caspase-3, and this is accompanied by the degradation of poly-ADP-ribose polymerase (156). The gene discussed is CASP9; the disease is prostate cancer.