CD47 and osteosarcoma: first identified the expression of CD47 on ovarian tumors as early as 1986 (28), and a series of studies subsequently confirmed that CD47 was highly expressed in both hematological and solid malignancies, including non-Hodgkin’s lymphoma (NHL) (29), chronic myeloid leukemia (CML) (17), myeloma (30), osteosarcoma (31), breast cancer (32), and other solid tumors.