Sep

13

Cancers of the Immune System

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The cells of the immune system, like other cells, can grow uncontrollably, resulting in
cancer. Leukemias are caused by the proliferation of white blood cells, or leukocytes. The uncontrolled growth of antibody-producing plasma cells can lead to multiple myeloma. Cancers of the lymphoid organs, known as lymphomas, include Hodgkin’s disease.

Source : National Cancer Institute (NIH Publication No:03-5423)

Sep

13

Immunity and Cancer

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When normal cells turn into cancer cells, some of the antigens on their surface may change. If the immune system notices the foreign antigens, it launches the body’s defenders, including killer T cells, NK cells, and macrophages. But the immune system cannot patrol everywhere to provide bodywide surveillance, flushing out and eliminating all cells that become cancerous. Tumors develop when the system breaks down or is overwhelmed. Scientists are shaping immune cells and substances into ingenious new anticancer weapons. They are using substances known as biological response modifiers, including lymphocytes and lymphokines, to bolster the patient’s immune responses. In some cases, biological response modifiers are injected directly into the patient. They can also be used in the laboratory to transform some of the patient’s own lymphocytes into tumor-hungry cells, which are then injected back into the patient so they can attack the cancer cells.
Antibodies specially made to recognize specific cancers can be coupled with drugs, toxins, or radioactive materials, then sent off like “magic bullets” to deliver their lethal cargo directly to the target cancer cells. Alternatively, toxins can be linked to a lymphokine and routed to cells equipped with receptors for the lymphokine. Radioactively labeled antibodies can also be used to track down hidden nests of cancer cells (metastases).
Still other researchers are testing therapeutic cancer vaccines. These differ from traditional vaccines, which are given before disease onset to protect a person from future infections. Cancer vaccines are used after the cancer has arisen, and are designed to help the immune system fight off the illness.
The immune system often responds weakly or not at all to cancer cells. Cancer vaccines try to improve on the natural anticancer response by stimulating strong killer T-cell responses against a tumor. Although such vaccines are generally not able to destroy a tumor if given as the only form of treatment, research suggests they can be effective partners if administered along with other forms of treatment.

Source : National Cancer Institute (NIH Publication No:03-5423)

Sep

13

What is Immune System

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The immune system is a network of cells, tissues, and organs that work together to defend the body against attacks by “foreign” invaders. These are primarily microbes(germs)—tiny, infection-causing organisms such as bacteria, viruses,parasites, and fungi. Because the human body provides an ideal environment for many microbes, they try to break in. It is the immune system’s job to keep them out or, failing that, to seek out and destroy them.When the immune system hits the wrong target or is crippled, however, it can unleash a torrent of diseases, including allergy, arthritis, or AIDS.The immune system is amazingly complex.It can recognize and remember millions of different enemies, and it can produce secretions and cells to match up with and wipe out each one of them.The secret to its success is an elaborate and dynamic communications network.Millions and millions of cells, organized into sets and subsets, gather like clouds of bees swarming around a hive and pass information back and forth. Once immunecells receive the alarm, they undergo tactical changes and begin to produce powerful chemicals. These substances allow the cells to regulate their own growth and behavior, enlist their fellows, and direct new recruits to trouble spots.

Source : National Cancer Institute (NIH Publication No:03-5423)