In addition to transfection of PC3 cells with PDEF, we also performed complementary RNA interference (RNAi) experiments to reduce the endogenous PDEF expression in prostate cancer cells that express PDEF (LNCaP and C4-2B cells), and directly evaluated the effects of decreased PDEF levels on invasion and clonogenic activity of these cells. This evidence concerns the gene SPDEF and prostate carcinoma.