Abstract:
Cancer is defined as the group of related disease which involves abnormal cell
growth with the potential to invade surrounding tissues and other parts of the
body. Many cancers form solid tumors which are malignant. There are many
differences between a cancerous cell and a normal cell. Cancer cells are less
specialised than the normal cells. While normal cells mature into very distinct cell
types, cancer cells do not and hence continue to divide without stopping. Cancer
cells are able to ignore signals such as apoptosis or programmed cell death, which
the body uses to get rid of unwanted cells. Cancer cells are able to influence the
normal cells, molecules or blood vessels that surround and feed the tumor (tumor
microenvironment). They also acquire the ability to evade immune system response.
Cancer is a genetic disease and the genetic changes that cause cancer can be
either inherited from parents or are acquired during a person’s lifetime as a result
of errors that occur during cell division or due to DNA damage caused by
certain environmental exposures like radiation such as UV rays or substances such
as chemicals in tobacco smoke or infections such as viral infections.
