CD47 and cancer: It has been implicated in tumor growth, invasion, and metastasis. Like CD47, CD24 is also a “don’t eat me signal”, acting as an inhibitor for Siglec-10 on macrophages and other immune cells. Furthermore, CD24 has been recognized as a marker for cancer stem cells, which are a small cell subpopulation within tumors that are notorious for their ability to self-renew and drive tumor recurrence. These cells are thought to be responsible for tumor recurrence and resistance to both chemotherapy and radiation therapy.