Leukemia was first described and named as a disease in 1845 by Rudolf Virchow, a physician at Berlin Charité University Hospital. It means “white bloodedness” and is derived from the milky discoloration of the blood in patients which is caused by the increased multiplication of white blood cells. This flood of leukocytes comprises immature and dysfunctional precursors which also prevents the formation of all types of normal blood cells in the bone marrow. The wide range of leukemia symptoms includes paleness, weakness, bleeding tendency, spontaneous bruising and a susceptibility to infections, though none are in any way specific to leukemia. Depending on the course of the disease, a distinction is made between acute and chronic leukemia and many other subtypes based on the cell types affected and their properties.