Each year, nearly 27,000 adults and more than 2,000 children in the United States
learn that they have a disease called leukemia.
Leukemia is a type of cancer. Cancer is a group of more than 100 diseases that have two important characteristics in common. One of those is that certain cells in the body become abnormal. The other characteristic is that the body keeps producing large numbers of these abnormal cells.
Leukemia is cancer of the blood cells. To understand leukemia, it is helpful to know about normal blood cells and what happens to them when leukemia develops.
The blood is made up of fluid called plasma and three types of cells. Each type has special functions.
White blood cells - help the body fight infections and other diseases.
Red blood cells - carry oxygen from the lungs to the body's tissues and take carbon dioxide from the tissues back to the lungs. The red blood cells give blood its color.
Platelets - help form blood clots that control bleeding.
Normally, blood cells are produced in an orderly, controlled way, as the body needs them. This process helps keep us healthy. When leukemia develops, the body produces large numbers of abnormal blood cells. In most types of leukemia, the abnormal cells are white blood cells. The leukemia cells usually look different from normal blood cells since they do not function properly.
There are several types of leukemia. They are grouped in two ways. One way is by how quickly the disease develops and gets worse. The other way is by the type of blood cell that is affected.
In acute leukemia, the abnormal blood cells are blasts and thus remain very immature and cannot carry out their normal functions. The number of blasts increases rapidly, and the disease gets worse quickly. In chronic leukemia, some blast cells are present, but in general, these cells are more mature and can carry out some of their normal functions. Also, the number of blasts increases less rapidly ...