GPI and myeloid leukemia: NLK is also known as glucose-6-phosphate isomerase or phosphohexose isomerase, an intracellular enzyme involved in glycolysis and gluconeogenesis [31], as autocrine motility factor, a tumor maturation factor in cancer cells, playing a role in metastasis [32] and as a maturation factor, mediating differentiation of human myeloid leukemia cells [33].