CASP9 and prostate cancer: These findings are consistent with prior reports showing that Spirulina-derived C-PC potentiated CDDP antitumor activity in Ehrlich ascites carcinoma-bearing mice [60] and that combining C-PC with topotecan increased cytotoxicity of LNCaP prostate cancer cells compared to topotecan alone, likely by augmenting caspase-3 and caspase-9 expression [61].