Cancer Essay, Research Paper

Cancer

Right now, cancer is one of the most feared diseases in the world. In

the early 1990s almost 6 million new cancer cases developed and more than 4

million deaths from cancers occurred. Also more than one-fifth of all deaths

were caused by cancer and it has been predicted, by the American Cancer Society,

that about 33% of Americans will eventually develop this disease. This is a huge

disease that is killing people all over the world.

The field of cancer study is called Oncology. The government has spent

billions of dollars on research of this fatal disease. Cancer is the most

aggressive disease of a larger class known as neoplasms. Neoplasms do not fully

comply with the parts of the cell that control the growth and functions of the

cell. These cells eventually become abnormal growths and can be recognized as

not normal tissue. These traits are passed down as the cell reproduces therefore

spreading the cancer.

Neoplasms are generally classified into two groups: malignant and benign.

Malignant tumors, or abnormal tissue, grow more rapidly than benign tissue and

they invade normal tissue. Benign tissue is structured similar to normal tissue

while malignant tissue is abnormal and has an unstructured appearance. Of

greater importance, benign tissue does not metastasize, or begin to grow in

other sites, like malignant tumors do. Cancer always refers to metastasized

tumors but the term tumor is not always necessarily cancer. A tumor is any

living tissue that is distinguishable as abnormal living tissue. After a

cancer forms, it can also change from a benign to a malignant state, therefore

making the cell grow at a more rapid rate. The development of the cell starts

when it forms notable abnormalities in chromosomes and then multiplies

exceedingly. Then metastasis usually occurs and generally causes the death of

the host. There are many different cancers which form on just about all parts of

the body. In the US, skin cancer is the most common cancer, then prostate

cancers in males, and then breast cancer in women. Leukemia is clearly the

dominant cancer in children. The number one killing cancer in the world today is

lung cancer, mostly caused by the smoking of cigarettes. Some researchers have

stated that if Americans stopped smoking, lung-cancer deaths could disintegrate

within two decades. Stomach cancer is the second most fatal cancer in males and

Third is the leading cancer in women, breast cancer. The prevention of

cancer rides upon what is known about the causes. Any agent that causes cancer

is called a carcinogen. Carcinogens are generally classified into three groups-

chemical, biological, and physical. Chemicals that cause cancer have many

different molecular structures and can be just about any type of chemical. Some

substances that cause cancer are complex chemicals and gases, certain metals,

drugs, hormones, substances in molds and plants and many more. Many

nitrosamines, or simple organic oxides of nitrogen, are carcinogenic. That and

hydrocarbons are carcinogens in cigarette smoke and increase the risk of lung

cancer. Also another chemical gas, vinyl chloride, gas has been found to be an

agent of sarcoma of the blood vessels in the liver. Many drugs as well as

alkylating agents used to treat cancer are carcinogenic. Even though these

chemicals break the DNA of cancerous cells, which kills them, it also induces

cancer in normal cells. Some hormones created in humans can also cause cancer.

High levels of estrogen, which is marked as a female hormone, can increase the

chances of getting a cancer of the uterus (in women). Aflatoxin B is a substance

produced by the mold Aspergillus that causes a number of cancer, but generally

liver cancer. Many carcinogens have not been discovered but research is being

done to discover other carcinogens to keep people aware and safe. There are also

many different biological agents which cause cancers. The most common biological

agents are the oncogenic viruses that commonly bring about the formation of

neoplasms in some smaller animals. Also some of these viruses are thought to

cause human cancers, and one has even been proven to cause leukemia. These

viruses can be split into DNA viruses and RNA viruses, depending on their

genetic structure. The DNA viruses generally insert the genetic information

straight into the cells of their host. The RNA virus, contrasting, requires that

the genetic information be transcribed into DNA by an enzyme, called reverse

transcriptase, provided by the virus. All onconogenic viruses have one or more

genes that are needed for the transformation of the infected cell into the

neoplastic cell. These genes, called oncogenes, are best portrayed in the

genomes of oncogenic RNA virus. It is now seen that the oncogenes have close

relation with the counterparts in the normal cells which they infect. The

oncogene, nonetheless, has a different structure and appears to be activated and

expressed abnormally by one mechanism or another, leading to transformation in

the cell. Some oncogenic viruses may activate the normal cellular counterparts

of oncogenes, called c-oncogenes, thus causing the neoplastic transformation to

occur. Similar reactions may be a result from the action of chemicals or

radiation or both. Ultraviolet and high-energy radiation are also agents for

some types of cancer. A bond exists between exposure to the sun?s ultraviolet

rays and the occurrence of skin cancer in humans. Some cancers caused by

radiation are leukemia, along with cancers of the thyroid, breast, stomach,

uterus, and bone. Consequently everyday diagnostic tools such as the X ray are

used very carefully so that a person is not overexposed. Physically induced

sarcomas can also be induced when films or disks are enclosed under the skin, as

done in experimental animals. After the implant has been in the animal for many

years, sarcomas usually develop around the implant. If the implant is pulverized

or its structure is markedly altered before insertion, no sarcomas develop. This

shows that the physical structure causes the cancer, other than the chemical

composition. Even though it is unknown why cancer happens in some people and not

in others heredity seems to have an effect in some forms of cancer. Because of

this, family history may be significant in predicting and diagnosing cancer.

Prevention is the best way to avoid cancer. Since the majority of cancer is

related to the environment, it would be best to identify and control these

factors. There are two tests to discover carcinogens. The Ames test measures the

ability of a substance to cause mutations in bacteria and is more than 90

percent effective. The alternative is animal testing. It is exhausting and

expensive work but it is the only certain way to be sure if a particular agent

is carcinogenic. One of the most important ways to protect yourself is early

detection. It is stressed that you get treatment as soon as possible. The

American Cancer Society has come up with seven warning signs of cancer to help

you identify cancer symptoms and get help early. They are: 1.a change in bowel

or bladder functions; 2.a sore that does not heal; 3.unusual bleeding or

discharge; 4.a thickening or lump on the body; 5.indigestion or trouble

swallowing; 6.an obvious change in a wart or mole; and 7. A nagging cough or

hoarseness. If one or more of these symptoms are present a person is advised to

see a doctor immediately.

If treatment of a cancer is to be successful, the diagnosis must be as

early as possible. Though no tests have been discovered to detect all cancers,

there are tests to pick up some. A pap test is used to search for cancer of the

uterine cervix. Mammograms are used to detect breast cancer and blood and stool

tests are used to find colon cancer. There are many other tests besides these to

test for all different types of cancer. There are really three different types

of cancer. Surgical removal is the first, it is the most basic treatment. It is

used to remove the cancerous legions in the body. The second is radiation

therapy, which uses radiation to try and kill the tumor. One of the main

problems with that is not only does it kill cancerous tissue, it also kills

healthy ones. The third way to treat cancer is chemotherapy, which is treatment

by chemical agents. The chance of complete cure is not common but it is usually

used to increase the life of the carrier. The desired effect of treatment in

cancer patients is remission, where the cancer is gone from your body and if it

does not return within 5 years it is considered cured.

Right now the government is spending huge sums of money on cancer

research. They are continuously finding cures and finding better ways to treat

and deal with cancer. Research has come very far and helped many people fight

cancers. Thanks to all the work done, cancer is still a dreaded disease but is

now curable which gives many people faith in recovery.

Bibliography

Compton?s Encyclopedia(1992). Cancer . Chicago: Compton?s Learning Company

Encyclopedia Britannica(1992). Cancer. Chicago: Encyclopedia Brittanica, Inc.

American Cancer Society website(1996): http://www.cancer.org/acs.html