Pediatric leukemia is a type of cancer that affects the blood and bone marrow, where blood cells are produced. It is the most common type of cancer in children. In leukemia, the bone marrow produces an excessive number of abnormal white blood cells, which can crowd out healthy blood cells and interfere with the body’s ability to fight infection, carry oxygen, and control bleeding. There are several types of pediatric leukemia, with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) being the most common.