_Cancer _
By: TJ
Final Draft T. J. Cox The problem is cancer. Cancer is the second
leading cause of death in the world and my interest in the subject is simple.
My mother is the most resilient person I have ever met. Any time I need any
kind of inspiration, I need only to think of her. When she was eighteen she
was diagnosed with Hodgkin’s disease. The doctors gave her a less than thirty
percent chance of living. Since then she has had cancer three other times.
Breast cancer twice in ‘85 and ‘90, and most recently, colon cancer two
summers ago. She has had many different treatments including chemo and
radiation therapy as well as surgery to remove lumps in both breasts and her
colonWhat is cancer? There are more than 100 different types of cancer. It
occurs when cells become abnormal and divide without control or order.
Normally, cells divide in an orderly way to produce more cells only when the
body needs them. If cells keep dividing when new cells are not needed, a mass
of tissue forms. This mass of extra tissue, called a growth or tumor, can be
benign or malignant. (National Institute of Health) Benign tumors are not
cancer. They do not invade nearby tissue or spread to other parts of the body.
Benign tumors usually can be removed and are seldom a threat to life.
Malignant tumors are cancer. They can invade and damage nearby tissues and
organs. Cancer can also break away from a malignant tumor and enter the
bloodstream and lymphatic system. Through the lymphatic system is one of
cancers best modes of transport for spreading to form new tumors in other
parts of the body. The spread of cancer is called metastasis. Malignant tumors
must be treated or will be fatal There are many treatments for cancer. Among
these are radiation, chemotherapy, surgery and the rapidly growing field of
genetic therapy. It was discovered that when radioactive waves were directed
on human cells, the cells would be destroyed. The idea of using this
technology on cancer was a good one but was unsuccessful at first due to the
damage caused to surrounding tissues. Then the analogy drawn from a simple
story gave insight on how to focus the rays on the cancer and not harm the
surrounding tissues and organs. The story goes like this A small country was
ruled from a strong fortress by a dictator. The fortress was situated in the
middle of the country, surrounded by farms and villages. Many roads led to the
fortress through the countryside. A rebel general vowed to capture the
fortress. The general knew that an attack by his entire army would capture the
fortress. He gathered his army at the head of one of the roads, ready to
launch a full-scale direct attack. However, the general then learned that the
dictator had planted mines on each of the roads. The mines were set so that
small bodies of men could pass over them safely, since the dictator needed to
move his troops and workers to and from the fortress. However, any large force
would detonate the mines. Not only would this blow up the road, but it would
also destroy many neighboring villages. It therefore seemed impossible to
capture the fortress. However, the general devised a simple plan. He divided
his army into small groups and dispatched each group to the head of a
different road. When all were ready he gave the signal and each group marched
down a different road. Each group continued down its road to the fortress so
that the entire army arrived together at the fortress at the same time. In
this way, the general was able to capture the fortress and overthrow the
dictator This simple story was the basis for intensity modulated
radiotherapy (IMRT). This is a technique used to treat cancerous tumors on
which a removal operation could not be performed. Interesting dose
distributions generated by IMRT allow a better sparing of normal tissues with
decreased acute and late toxicity, and offer a window for further dose
escalation’s. (De Neve W; Claus F; Van Houtte P; Derycke S; De Wagter C) In
order to get a radiation beam of high enough intensity to hit the tumor,
without damaging surrounding tissues, several lower intensity beams were
directed to the tumor from different directions. This method decreases damage
to surrounding tissues but, it does not work on all cancer and still has some
side effects Another method with side effects used to treat cancer is
chemotherapy. Chemotherapy is a word to describe chemical agents (drugs) that
are used in the treatment of various types of cancer. (Medical Oncology and
Hematology Associates) Chemotherapy works by killing rapidly dividing cells.
Cancer cells are rapidly dividing, but unfortunately so are white blood cells,
red blood cells, platelets, cells lining the mouth, stomach and intestines,
hair cells, and reproductive cells. These factors are part of the reason there
are so many side effects with chemotherapy. Damage to these other rapidly
dividing cells lead to loss of hair, nausea, sore mouth and decreased immune
response The side effects still associated with radiation and chemotherapy
have led many researchers to look to new areas for cures. The breathtaking
pace of gene discovery in the last two decades, coupled with the birth of
recombinant DNA technology, gave rise to the concept that genes may be
manipulated and used as drugs. (Kong HL) Family friend and nationally renown
genetic therapist, Ken Culver is working on genetic cures for cancer. One
technique he and his team are pioneering is the idea of injecting the genetic
code of a curable disease into a cancerous lump via recombinant DNA. The
theory is that the disease will take over the cancerous cells and then the
lump can be cured by the cure for the disease. Gene therapy has the potential
to provide cancer treatments based on novel mechanisms of action with
potentially low toxicities. (Roth JA; Swisher SG; Meyn RE) Many of you have
probably heard of cancer patients taking a variety of medicines and varying
doses. It has been found that naturally occurring P-glycoproteins help in the
build up of resistance to this multidrug technique. In a present study, the
pharmokinetics of doxorubicin, a P-glycoprotein modulator, and GF120918, a
novel potent P-glycoprotein inhibitor, were examined in cancer patients in a
search for more selective modulation of multidrug resistance (MDR).
(Sparreboom A., Planting A. S., Jewell R. C., van der Burg M. E., van der
Gaast A., de Bruijn P., Loos W. J., Nooter K., Chandler L. H., Paul E. M.,
Wissel P. S., Verweij J.) Data indicates that GF120918 at the tested doses of
combination treatment achieves plasma concentrations that reverse MDR in
experimental models and it lacks the significant kinetic interaction with
doxorubricin observed previously with other modulators. (7) Another study
found that although multiple genes are involved in carcinogenisis.
Carcinogenisis is the mutating of DNA because of a chemical in the body.
Mutations of the p53 gene are the most frequent abnormality identified in
human tumors. High levels of p53 expression and DNA-damaging agents work
synergistcally to induce apoptosis (cell death) in cancer cells. Phase I
clinical trials now show that p53 gene replacement therapy using both
retroviral and adenoviral vectors(these are ways of getting the replacement
genes into the cell) is feasible and safe. (Roth) Carcinoma, cancer of the
epithelial cells, is a major cause of mortality in western societies. Clonal
fixation and propagation of genetic changes due to oncogenes(cancer causing
genes), sporadically accumulating in the epithelial cells, depend on growth
factors and their surface receptors. One of the large families of receptors is
that of the ErbB tyrosine kinases. ErbB-2 delays ligand dissociation, enhances
coupling to the mitogen-activated protein kinase pathway, and impedes the rate
of receptor downregulation. The realization that ErbB-2 is a master regulator
of a signaling network that drives epithelial cell prolification identifies
this protein as a target for cancer therapy. (Klapper LN; Kirschbaum MH; Sela
M; Yarden Y) Cancer is still the second leading cause of death in the world.
All though the outlook on where research is going is optimistic, I still feel
that the faith of the patient is large factor. I have had many talks with Ken
Culver about patients he has had in the past. One in particular stands out.
The patient had a malignant tumor in her lung. She went through every
treatment the doctors thought might work and nothing did. The doctors said it
was only a matter of time and told her to enjoy the weeks she had left. To
their surprise a month later she was improving and after two months the tumor
was gone. When they asked her what she had done in the past two months she
talked about positive mental imagery. She said she pictured the tumor as a
large block of cheese and her immune system as a pack of mice. She envisioned
the mice gnawing away on the cheese and she just started feeling better and
better. The doctors had no explanation as to how the woman was sitting in the
office telling them all this Cancer is a horrible disease that effects
millions of people every year. Further improvements are being made in past
treatment techniques, and new theories are being formulated as we speak. There
are so many different types of cancer that there will never be one pill that
can be taken as a cure. Hopefully the rapid new findings in gene therapy will
be what the world needs to beat the plague of the twentieth century.
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