This interaction illustrates the growth and spread of a type
of cancer known as carcinoma. Carcinomas originate in the
body's epithelial tissues, which are thin cell layers, often
a single cell deep, that line body cavities and outer
surfaces. Epithelial tissues are found in many organs and
glands.
Within every nucleus of every one of the human body's 30
trillion cells exists DNA, the substance that contains the
information needed to make and control every cell within the
body. Here is a close-up view of a tiny fragment of DNA.
This piece of DNA is an exact copy of the DNA from which it
came. When the parent cell divided to create two cells, the
cell's DNA also divided, creating two identical copies of
the original DNA.
