Evaluation of sunitinib treatment in a human xenograft OS mouse model indicated slowed tumor growth, reduced primary tumor vascularization, and inhibition of lung metastasis.199 Sunitinib single-agent treatment in a mouse model of bone metastatic breast cancer significantly reduced tumor growth and also decreased ACP5+ osteoclast numbers at the tumor-bone interface. The gene discussed is ACP5; the disease is neoplasm.