CD antigens and other antigens have been used extensively as cell surface markers to determine the phenotype of normal and abnormal cells. For example, CD34+ and CD38− phenotypes are present in groups of normal hematopoietic stem cells, can also be seen in common leukemia stem cells (LSC) which produce acute myeloid leukemia (AML). Therefore, multifunctionality, including self-renewal, survival, proliferation and differentiation are important steps for the origin of cancer stem cells which under certain conditions develop into a malignancy. Non-CD markers are constantly changing. They reflect conditions and happeniings inside of the cell upon which they're found.