What is Leukemia?

Leukemia is a type of cancer in which certain white blood cells grow out of control and spread through the blood stream. These white blood cells are made in the bone marrow. Bone marrow is the spongy material in the center of bones where our blood cells are formed. The leukemia blood cells are not normal and cannot do their usual work. They also interfere with other blood cells working properly. There are four main types of Leukemia that are grouped and named by:

  • Whether it is Acute (fast growing) or Chronic (slow growing).
    • Acute leukemia grows rapidly
    • Chronic leukemia grows slowly
  • The type of white blood cell that is affected (called a myeloid cell or a lymphoid cell)

The most common types of Leukemia are called:

Understanding Blood Cells

Blood is a liquid consisting of plasma and blood cells. The different cells are called: red blood cells, white blood cells, and platelets.

  • Plasma is mostly water with proteins, salts and minerals
  • Red blood cells (RBC) are small, red-colored cells that carry oxygen to all cells of the body
  • White blood cells (WBC) are cells of the immune or infection-fighting system. The immune system cells trap and destroy bacteria and other cells that might cause us harm. There are several different kinds of WBC, including two kinds of lymphocytes: T lymphocytes and B lymphocytes
    • B lymphocytes help make special proteins (antibodies) that guard against harmful cells or organisms.
    • T lymphocytes help the B cells identify the harmful cells that need to be killed and sometimes kill harmful cells directly
  • Platelets are fragments of blood cells that are needed for blood to clot

Blood cells are made in the bone marrow, the spongy center inside most bones. Most blood cells grow from early cells called stem cells. When the white blood cells mature, they move into the blood vessels where they travel throughout the body.

When we are in good health, the numbers of the different blood cells are kept in proportion to the jobs they do. In the different types of leukemia, too many of a particular blood cell are made, often immature cells called blasts. Blast cells do not fight infection.

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