- Red blood cells that carry oxygen and other materials to all tissues of the body.
- White blood cells that fight infection and disease.
- Platelets that help prevent bleeding by causing blood clots to form.
The lymphoid stem cell develops into a lymphoblast cell and then into one of three types of lymphocytes (white blood cells):
- B lymphocytes that make antibodies to help fight infection.
- T lymphocytes that help B lymphocytes make antibodies to fight infection.
- Natural killer cells that attack cancer cells and viruses.
There are three ways that cancer spreads in the body.
When cancer cells spread outside the blood, a solid tumor may form. This process is called metastasis. The three ways that cancer cells spread in the body are:
- Through the blood. Cancer cells travel through the blood, invade solid tissues in the body, such as the brain or heart, and form a solid tumor.
- Through the lymph system. Cancer cells invade the lymph system, travel through the lymph vessels, and form a solid tumor in other parts of the body.
- Through solid tissue. Cancer cells that have formed a solid tumor spread to tissues in the surrounding area.
Chronic Lymphocytic Leukemia Treatment (PDQ®) URL at:
(Accessed on 25/04/12)