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)
tumor.
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
liver.
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.
About the author:
canro dicausa is the owner of
RUS Cancer
which is a premier resource for cancer information.
for more information, go to http://www.ruscancer.com
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