multi-step genetic disease, which begins with a mutation of a normal cell, allowing the initiated cell to grow unrestrained.  The complexities of this carcinogenesis process are becoming better known, including the roles of oncogenes and suppressor genes.

One of the most complex organ systems is that of the nervous system. Two categories of cells are found in the nervous system, neurons and glial cells.  Neurons are the functional nerve cells that transmit information to and from the CNS.  Glial cells provide support and regulate the