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Disclaimer: Term papers are for research purposes only.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
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