In addition to its role in cellular metabolism, outside the cell, GPI/AMF acts as a cytokine, and this function is dependent on the interaction with its membrane receptor, AMFR/gp78.26,32 In particular, GPI/AMF plays a role as a maturation factor for human myeloid leukemia cells, is a neurotrophic factor for embryonic spinal and sensory neurons, is involved in sperm agglutination, is a myofibril-bound serine proteinase inhibitor, and has a role in the development of somatosensory and motoric neural structures.33–37. Here, GPI is linked to myeloid leukemia.