CDK4 and osteosarcoma: Group B included ten osteosarcomas, spanning low- and high-grade cases (three parosteal, two low-grade central, three dedifferentiated parosteal, and two conventional), all displaying amplification of CDK4 and MDM2, along with regions on chromosome arm 12p in all but three cases (Figs. 1 and 3A; Supplementary Figs. 3–13; Supplementary Table 1).