ACP5 and prostate cancer: Additionally, the number and extent of mature osteoclasts in the bone-tumor interface of PC3shGFP-injected tibias were much higher than those of PC3shADAM9-injected tibias, as determined by tartrate-resistant acid phosphatase (TRAcP) staining (p<0.01) (Fig. 2e), indicating that silencing the expression of ADAM9 reduced the ability of prostate cancer cells to induce osteoclastogenesis in the bone.