CD47 and acute lymphoblastic leukemia: In the 1980s, Knauf et al.11 first discovered the expression of CD47 on ovarian cancers, subsequently, a series of studies have confirmed that CD47 is overexpressed on tumor cells compared with healthy cells, including acute lymphoblastic leukemia cells12, lymphoma cells7, non-Hodgkin’s lymphoma (NHL) cells13, glioblastoma14, myeloma cells15, bladder tumor cells16, head and neck squamous cell carcinoma cells17, breast18, pancreas19, liver20, lung21, and prostate cancer cells22.