SP7 and osteosarcoma: Osterix (OSX), also known as SP7, is a zinc finger transcription factor that is usually expressed in osteoblasts to regulate osteoblast differentiation and maturation.4 The expression of OSX had been suggested to be limited to bone tissues; however, recent studies identified that OSX was overexpressed in various cancer tissues, such as osteosarcoma, prostate cancer and breast cancer.5, 6, 7 Nevertheless, there have been few studies on the role of OSX in carcinogenesis.