Leukemia

In people with leukemia, the bone marrow produces abnormal white blood cells.  (Normal blood cells).

The types of leukemia are grouped by how quickly the disease develops and gets worse. Leukemia is either chronic (gets worse slowly) or acute (gets worse quickly):

• Chronic leukemia—Early in the disease, the abnormal blood cells can still do their work, and people with chronic leukemia may not have any symptoms. Slowly, chronic leukemia gets worse. It causes symptoms as the number of leukemia cells in the blood rises.

• Acute leukemia—The blood cells are very abnormal. They cannot carry out their normal work. The number of abnormal cells increases rapidly. Acute leukemia worsens quickly.

The types of leukemia are also grouped by the type of white blood cell that is affected. Leukemia can arise in lymphoid cells or myeloid cells. Leukemia that affects lymphoid cells is called lymphocytic leukemia. Leukemia that affects myeloid cells is called myeloid leukemia or myelogenous leukemia.

There are four common types of leukemia:

• Chronic lymphocytic leukemia (chronic lymphoblastic leukemia, CLL). Most often, people diagnosed with the disease are over age 55. It almost never affects children.
• Chronic myeloid leukemia (chronic myelogenous leukemia, CML).  It affects mainly adults.
• Acute lymphocytic leukemia (acute lymphoblastic leukemia, ALL). It is the most common type of leukemia in young children. It also affects adults.
• Acute myeloid leukemia (acute myelogenous leukemia, AML).  It occurs in both adults and children.

 Video (Dr. Leonard Sender, Director of Oncology for at UC Irvine discusses leukemia in the younger population.) 

Normal Blood Cells

Blood cells form in the bone marrow. Bone marrow is the soft material in the center of most bones.

Immature blood cells are called stem cells and blasts. Most blood cells mature in the bone marrow and then move into the blood vessels. Blood flowing through the blood vessels and heart is called the peripheral blood.

The bone marrow makes different types of blood cells. Each type has a special function:

• White blood cells help fight infection. 
   
• Red blood cells carry oxygen to tissues throughout the body. 
   
• Platelets help form blood clots that control bleeding. 

Source:  National Cancer Institute