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.
