The Z-VAD-FMK pan-caspase inhibitor interfered with the P5091-induced citotoxicity in hormone sensitive and in androgen-independent prostate cancer cells (Figure 1D); moreover, the caspase 3 was activated upon P5091 treatment in both the cell lines (Figure 1E), suggesting overall that the reduced number of cells induced by P5091 treatment is due to apoptosis mediated, at least in part, by caspases. This evidence concerns the gene CASP3 and Familial prostate cancer.