CSF3 and neutropenia: Granulocyte colony-stimulating factor (G-CSF, molecular weight about 20,000) is a glycoprotein which regulates especially the production of neutrophils; it is produced by activated macrophages, endothelial cells and fibroblasts; using recombinant DNA technology, G-CSF can be produced in large quantity in Escherichia coli and mammalian cells, and it is widely used clinically to treat patients suffering from neutropenia after cancer chemotherapy [5].