This essay Cancer has a total of 3924 words and 17 pages.
Of all the diseases and viruses that are known to man, no other can strike fear in so many people's hearts, as the word cancer. What is cancer? Cancer is a new growth of tissue resulting from a continuous proliferation of abnormal cells that have the ability to invade and destroy other tissues.1 Cancer may be found in any type of cell or tissue in the human body. Cancer is not found in just humans, but also in animals and plants. Cancer cells can grow where ever normal cells grow or divide. Cancer is not one disease but many single diseases classified under one name.2
In our bodies we produce many thousands of new cells everyday. We produce these cell in order to grow until we reach adulthood. When we reach adulthood, these cells reproduce primarily to heal wounds and to replace the cells that have died.3 When we look at a cancerous cells, we see that it divides endlessly. As the cell divides and multiplies, it takes up more and more of the space that the healthy cells once had to work in. These cells will take up more and more space until they are able to move into new areas of the body or the organism in which they live dies. This process of moving to new sites within the body is called metastasis.4
1. Robert A. Weiberg, Racing to the Beginning of the Road,Random House 1996, pg. XI.
2. Excerpted from Compton's Interactive Encyclopedia,1994,NewMedia, Inc.
3. R. Grant Steen, The Basic Science of Cancer, Plenum Press, 1993, pg. 31.
4. Steven A. Rosenberg, The Transformed Cell G.P. Putnam's Sons, 1992, pg. 341.
There are many different types of cancer. Out of the hundreds of different types of cancer, there are three sub types to help classify the different types of cancer.
First, Sarcomas, arise from connective and supportive tissue such as bone, cartilage, blood vessels, muscle and fat.
Second, Carcinomas, which include the most frequently occurring forms of human cancer, arise from epithelial tissue, such as the skin and the lining of the body cavities and organs, and the glandular tissue of the breast and prostrate. Carcinomas with a structure resembling skin are termed squamous cell carcinomas. Those that resemble glandular tissue are called adenocarcinomas.
Third, Leukemias and lymphomas include the cancers that involve blood forming tissues and are typified by the enlargement of the lymph nodes, the invasion of the spleen and bone marrow and the over production of immature white cells.5
The only number greater than the number of different types of cancer is the number of people found to have these deadly diseases. One million new cases of cancer are diagnosed in the United States alone each year. Five hundred thousand die each
5. Excerpted from Compton's Interactive Encyclopedia, 1994.
year from this disease. It is also estimated that about 30% of the Americans living today, or 76 million Americans will develop cancer in their lifetime.6
As scientist search to cure this terrifying disease, with the help of millions of dollars in donations, we still do not even know what causes cancer to invade. We do understand that the diseases likeliness to form is heightened with the different environments that people live in. Researchers see that with constant contact with carcinogens, substances that promote the development of cancer, is almost a guarantee that the person will develop cancer at some point in their life.
Chemicals, radiation and viruses are the main types of carcinogens. Constant exposure to these carcinogens cause gene abnormalities that can be inherited or induced in a body cell. These cells can also be damaged by outside sources. After many mutations from these carcinogens, it is thought that mutations will occur and will produce a malignant cell that will copy itself into many cancerous cells.
Viruses are the cause of about 15% of all cancers. The virus is able to invade cells and cause them to synthesize new viral particles; viruses carry oncogenes that can
6. Excerpted from Encarta Encyclopedia, 1997.
infect cells and cause malignant transformation. Chromosomal structure change has been observed in 90% of all human cancer. Chromosomes are the repository for all genetic information required to build a cell. 7 Chromosomal changes are now considered as common in malignant cells and used to diagnosis cancer.
It is said that about
Topics Related to Cancer
RTT, Anatomical pathology, Infectious causes of cancer, Oncology, Carcinogenesis, Cancer, Skin cancer, Carcinoma, Prostate cancer, Breast cancer, Neoplasm, Metastasis