TPO and cancer: Bone turnover contributes to tumor localization, and bisphosphonates, which suppress bone turnover, have been used effectively for the management of cancer-induced skeletal metastasis.(4,26–28) Since MKs potently inhibit osteoclastogenesis in vitro,(16) expansion of MKs with TPO may result in reduced osteoclast activity in vivo, which also inhibits prostate carcinoma cell growth in the bone marrow.