CD47 and cancer: CD47 is essential for the maintenance of hematopoietic stem cells, erythrocytes and platelets, but is also upregulated by cancer cells as a means of immune escape.92 Targeting CD47 and blocking its signaling through SIPRα, for example with a mAb, could overcome this tolerogenic pathway, increase the ability of phagocytes, such as macrophages, to phagocytose cancer cells and facilitate or enhance cancer cell killing.92,93 This is of great interest in melanoma, due to the abundance of macrophages within the TME.