TNFRSF9 and breast cancer: Treatment of mice bearing 4T1 breast cancer cells with NP-αCD137 Ab-F4/80 nanoparticles resulted in in vivo inhibition of bone and lung metastases, suggesting that NP-αCD137 Ab-F4/80 nanoparticles blocked the CD137 signaling and compromised the migration property of macrophages to tumor areas 217.