Cancer :: essays research papers fc

I chose to do my report on cancer because it is a subject I want to learn about and because it can probably fit 5 pages. My bibliography is on the ending of the report, my teacher helped me with it because I didnt know how to do it. Cancer is the name for tumors that are malignant. Malignant tumors do not respond to body mechanisms that limit growing. Malignant tumors show a not normal cell structure the same functional specialized cells. Also cancer cells growing in laboratory tissue culture do not stop growing when they touch each other on a glass or other solid surface but grow in masses several layers deep they are said to lack contact inhibition.   Ã‚  Ã‚  Ã‚  Ã‚  Loss of contact inhibition accounts for two other characteristics of cancer cells invasiveness of surrounding tissues and metastasis spreading via the lymph system or blood to other tissues and organs. Cells are typically controlled by growth factors competence factors that stimulate cells to enter the beginning phase of cell replication and progression factors that insure completion of the replication cycle. The unrestricted growth rates of cells are due to the activation and lack of inhibition of oncogenes. They are cancer causing genes.   Ã‚  Ã‚  Ã‚  Ã‚  Cancer tissue that grows without limits competes with normal tissue for nutrients kills the normal cells by nutritional deprivation. Cancerous tissue also causes secondary effects with the symptoms of a malignant growth caused by the pressure of the growing tumor against surrounding tissue or the metastasis of cancer cells and their invasion of other organs. Cancers are graded as to degree of malignancy on a scale of one through four the distinction between even benign and malignant neoplasms is obscure. All organs and tissues are susceptible to cancer.   Ã‚  Ã‚  Ã‚  Ã‚  A lot of human cancers may be caused or at least triggered by various chemical agents. Alkylating agents are thought to have a carcinogenic effect because they chemically alter the cell's nucleic acids. Nitrites common additives in processed meat react with amines in the stomach to form nitrosoamines which some authorities believe may be carcinogenic to humans. Other commonly occurring carcinogens are azo dyes, polycyclic hydrocarbons, and urethane. Certain carcinogens present occupational hazards. Asbestos particles once inhaled stay in the lung and act as an irritant. In the asbestos and construction industries workers have a high probability of developing a fatal cancer of the chest lining or abdominal lining 25 to 30 years after the initial inhalation of . Asbestos also has been linked to lung and colon cancers in exposed individuals. Oral cancer common in India is commonly attributed to the chewing of betel nuts. Although the apparently increasing incidence of some types of highly malignant