To determine the mechanism underlying macrophage-dependent CD47 upregulation in tumor cells, we generated macrophage-conditioned media by following these procedures: HOS cells were treated with DMSO or doxorubicin for 24 h, and then refreshed with serum-free medium for another 24 h to produce DMSO-treated tumor-conditioned medium (T-CMDMSO) or doxorubicin-treated tumor-conditioned medium (T-CMDOX). Here, CD47 is linked to neoplasm.