Wednesday, 4 February 2009

The Cause Of Cancer

Cancer is the disease of the cells. It is an abnormal 
growth of cells, which tend to reproduce in an 
uncontrolled way and, in some cases, spread or 
metastasize. A cancerous growth or tumor is also 
known as a malignant growth or tumor. A growth or 
tumor, which is non-malignant is called benign. Such 
tumors are not cancer. 

Cancer is not a single disease. It is a group of more 
than hundred different and distinctive diseases. It is not 
contagious. Cancer can involve any tissue of the body 
and have many different forms in each body area. Most 
cancers are named for the type of cell or organ in which 
they start. If a cancer spreads (metastasizes), the new 
tumor bears the same name as the original(primary) 

Cancer is the Latin word for crab. The ancients used 
the word to mean a malignancy, doubtless because of 
the crab-like tenacity a malignant tumor sometimes 
seems to show in grasping the tissues it invades. 
Cancer may also be called malignancy, a malignant 
tumor, or a neoplasm (literally, a new growth). 

In medicine, common term for neoplasms, or tumors, 
that are malignant is known as Cancer. Like benign 
tumors, malignant tumors do not respond to body 
mechanisms that limit cell growth. Unlike benign 
tumors, malignant tumors consist of undifferentiated, or 
unspecialized, cells that show an atypical cell structure 
and do not function like the normal cells from the organ 
from which they derive. Cancer cells, unlike normal 
cells, lack contact inhibition; 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. 

Cancer results from mutations of certain genes that 
allow the cells to begin their uncontrolled growth. These 
mutations are either inherited or acquired. Acquired 
mutations are caused by repeated insults from triggers 
(e.g., cigarette smoke or ultraviolet rays) referred to as 
carcinogens. There is usually a latency period of years 
or decades between exposure to a carcinogen and the 
appearance of cancer. This, combined with the 
individual nature of susceptibility to cancer, makes it 
very difficult to establish a cause for many cancers. 

The most significant avoidable carcinogens are the 
chemical components of tobacco smoke. Dietary 
components, like excessive consumption of alcohol or 
of foods high in fat and low in fiber rather than fruits and 
vegetables that contain antioxidants and necessary 
micronutrients, have also been linked with various 
cancers. Some cancers may be triggered by hormone 
imbalances. For example, some daughters of mothers 
who had been given DES (diethylstilbestrol) during 
pregnancy to prevent miscarriage developed vaginal 
adenocarcinomas as young women. Aflatoxins are 
natural mold byproducts that can cause cancer of the 

Certain carcinogens present occupational hazards. For 
example, in the asbestos industry, workers have a high 
probability of developing lung and colon cancer or a 
particularly virulent cancer of the mesothelium (the 
lining of the chest and abdomen). Benzene and vinyl 
chloride are other known industrial carcinogens. 

Risk to humans from carcinogens depends upon the 
dose and a person's biologic susceptibility. Factors 
influencing a person's biological susceptibility to cancer 
include age, sex, immune status, nutritional status, 
genetics, and ethnicity. 

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