Cancer related to blood cells is called as Leukemia. Under Leukemia condition, bone marrow produces abnormal cancerous blood cells that crowd out the normal and healthy blood cells. Leukemia is of different types based which blood cell type has become cancerous. White blood cells are more to prone to become cancerous than RBCs and platelets. Leukemia can be acute or chronic and Lymphocytic or Myelogenous. It occurs most commonly in adults above 55 years and children younger than 15 years. The treatment methods used depend on the blood cell affected and whether the leukemia is acute or chronic or Lymphocytic or Myelogenous. Chemotherapy is frequently used to treat leukemia.