A: Immunohistochemical analysis of RANKL in C4-2 tumored tibiae of control, prevention, and treatment groups. Paraffin-embedded C4-2 tumored tibiae of the SCID mice were sectioned and stained for RANKL (negative control staining is shown in inset box). The tumor cells stained positively for RANKL. B: Blood was collected to determine serum PSA levels by IMx Total PSA assay. Serum PSA levels were not significantly different between the C4-2 control with PBS injections (control), C4-2 with a concomitant subcutaneous injection of huRANKL MAb (5 mg/kg once a week) at implantation (prevention group), or C4-2 with a subcutaneous injection of huRANKL MAb (5 mg/kg biweekly, starting 3 weeks after implantation of C4-2 cells) (treatment group). Results are presented as mean ± SE.