By definition, cancer is a disease of the genes. A
gene is a small part of DNA, which is the master molecule
of the cell.Genes make proteins,which serve as the
workhorses of the body’s cells.
These proteins allow the
body to carry out all of the many processes that permit
breathing, thinking, moving, and others often taken for
granted.
Throughout people’s lives, the cells in their bodies
are growing, dividing, and replacing themselves.
Many genes produce proteins that are involved in
controlling the processes of cell growth and division.
Any alteration, or mutation, to theDNAmolecule can
disrupt the genes and produce faulty proteins. This
causes the cell to become abnormal and lose the
restraints on its growth.
The abnormal cell will begin
to divide uncontrollably. The new growth it forms will
be called a tumor or neoplasm.
Not all tumors are
cancerous. Those that are cancerous spread to other
parts of the body near the original cancer site or to
distant sites. Cancerous tumors are called malignancies.
A tumor that is not cancerous is called benign.
Cancer can occur in anyone and is the second leading
cause of death in the United States. Although cancer
may be inherited, it also may occur due to certain environmental
risk factors or behaviors.
For example, it is
well known that smoking can lead to lung cancer or that
unprotected sun exposure is a risk factor for skin cancer.
Diet and physical activity also play a role in cancer risk.
