Radiation, Chemotherapy and Surgery are considered to be the three frontline
weapons in a conventional war against cancer. A fourth weapon, largely
considered experimental, is "immunotherapy." Immunotherapy seeks
to use the body's immune system to fight against cancer. In the abstract,
the theory sounds elegant, useful and realistic. But the devil is in the
details. Putting the theories into practice will take much time, money,
blood, sweat and tears.
The body is blessed with natural defense mechanisms the guard against foreign
invaders, like bacteria, viruses and cancer cells. Research has found
that the body can distinguish between healthy cells and cancer cells and
eliminate the cancer cells. Full blown cancer develops when the body's
immune system is overwhelmed. Immunotherapy is designed to rebuild or
stimulate the immune system to fight back.
The body's internal army that fights against the foreign invaders is
spearheaded by the white blood cell, or lymphocyte. The lymphocytes search
for the invader, and once identified, unleash little sharpshooters called
T cells or B cells. The T cells are generated in the body's thymus
gland high in the chest. The thymus gland is like a munitions dump. The
Killer T cells, once unleashed and after locking onto their enemy target,
destroy the invader directly. Another weapon in the T Cell arsenal is
the lymphokine-producing T cell. It releases a protein called a lymphokine,
which includes interferons and interleukin -2. These proteins speed up
and bolster the immune system's force field against foreign attack.
The strategy is to create an "immune response" against the cancer
cell. Each cell in your body has an identical copy of your unique DNA
code. The DNA molecule is like your own personal identity card, which
screens all sister and brother cells to see if they belong. Cells that
do not contain your unique DNA code are redlined as invaders. The surfaces
of these invader cells are studded with molecules called "antigens".
The scientists in the lab coats try to develop vaccines or antibodies
that are programmed to recognize and defend against certain antigens.
Biological therapies include interferons, interleukins, tumor necrosis
factors, monoclonal antibodies and cancer vaccines. These may prove beneficial
when used in combination with each other and/or with conventional treatments.
Interferons are types of cytokines (cancer cell killing proteins) that
occur naturally in the body. There are three kinds, of which interferon
alpha is currently the most widely used (for hairy cell leukemia ). Interferons
can improve a patient's immune response against cancer cells by inhibiting
the cancer cell's growth or promoting their development into normally
behaving cells. The FDA has approved their use for hairy cell leukemia,
kaposi's sarcoma (which often arises in AIDS patients), and chronic
Interleukins are also cytokines that occur naturally in the body. They
can also be created in a test tube. Interleukin-2 (IL-2) has been the
most widely studied interleukin. IL-2 stimulates the growth of many immune
cells, such as lymphocytes (and Killer T cells). Lymphocytes that have
been supercharged with IL-2 have been shown effective in destroying certain
tumors. The game plan is to remove the lymphocytes from the cancer patient's
blood, boost them with IL-2 in the test tube, and re-inject the cancer
killing cocktail in the patient. The goal is to fortify the besieged patient's
anticancer immune response. IL-2 therapy has worked best with metastatic
Monoclonal Antibodies (MOABs) were originally lauded back in the late 1970s
by cancer researchers as the "magic bullet." These antibodies
are made in the laboratory and are cloned from the same living parent
cell. MOAB are specific for a particular cancer cell membrane antigen.
MOABs are made by injecting human cancer cells into mice so that their
immune systems will manufacture antibodies against these cancer cells.
The mouse cells that are producing the antibodies are then removed and
fused with a hybrid cell (a hybridoma). Hybridomas are like factories
that pump out large quantities of pure MOABs.
MOABS are being tested in clinical trials in patients with lymphomas, colorectal
cancer, lung cancer, and leukemia.
Like other forms of treatment, immunotherapies can cause serious side effects.
They are normally administered by injection, which may engender swelling
and rashes at the site of the shot. Interferons and interleukins can cause
flu- like symptoms. They may affect blood pressure. Side effects with
IL-2 can be severe and patients need to be closely monitored. Most trials
require the patient's doctor to obtain the immunotherapy agent and
inject same in the doctor's office. You can learn more about a particular
therapy and the logistics by calling the National Cancer Institute's
toll free number at 1-800-422-6237.
National Cancer Institute,
For a listing of clinical trials:
(listing over 1,400 current trials, with information about the researchers
and the medical facilities).
National Comprehensive Cancer Center Network