QPCTL and neoplasm: According to the different signaling pathway blocking sites, the strategies for inhibiting the CD47-SIRPα interaction can be divided into three types: molecules that inhibit the CD47 protein on the tumor cells, molecules that inhibit SIRPα protein on the myeloid cells, and inhibitors of the glutaminyl-peptide cyclotransferase-like (QPCTL) enzyme, which is necessary for the maturation of CD47 protein (Logtenberg et al., 2020).