It is a form of cancer which affects the blood, or bone marrow. Sufferers have a very high white blood cell count. It affects both children and adults, though it is commonly thought of as a children's disease.
Leukemia is a type of cancer that targets the blood and or bone marrow. All cancer is terrible but leukemia is especially menacing because blood (which is produced in bone marrow) is a main component of the immune system.