LEUKEMIA

Leukemia is sometimes not considered a true cancer, because leukemia involves blood cells circulating through the body rather than a fixed mass of tissue. However, leukemia cells, when studied under the microscope and in cells cultures, behave like cancer cells found in tumors. There are both acute and chronic forms of leukemia, such as acute granulocytic leukemia and chronic lymphocytic leukemia,named after the particular kind of white blood cells that are most affected. Leukemia affects the blood-forming tissues,such as the bone marrow, resulting in an overproduction of white blood cells.The disease is particularly lethal to children under the age of 15; more than 10 percent of the leukemia deaths each year is among children. The acute granulocytic leukemia can occur at any age, but the chronic lymphocytic leukemia usually does not appear before the age of 40. Source: The New Complete Medical and Health Encyclopedia