As shown in Figure 5b, siRNA transfection of DR 5 also blocked upregulation of DR 5 and cleavage of PARP and caspase 8 induced by EP in DU 145 prostate cancer cells (Figure 5b) indicating that DR 5 mediates EP induced apoptosis in DU 145 cells. This evidence concerns the gene CASP8 and prostate carcinoma.