_{Cancer
is the second leading cause of death in the nation resulting annually in
553,400 deaths nationwide and 13,000 deaths in Virginia. These
grim statistics indicate that although progress has been made on
many fronts in the war against cancer, much remains to be done.}

Cancer arises when normal cells within our body begin to behave in an uncontrolled manner. the cancer cells continuously replicate forming masses of cells, which are referred to as tumors. The cancer cells also spread throughout the body forming tumors at distant sites, which are called metastases. This loss of control occurs because some of the 10,000 or more instructions that control cell behavior becomes corrupted. These 10,000 or more instructions arises from the genes in the cell's nucleus. The instructions are referred to as messenger RNA (mRNA) and process of creating the instructions is referred to as gene expression. It is now clear that the instructions become corrupted because certain important control genes in the cancer cell become either inactivated (turned off), or in some cases, inappropriately activated (turned on) by mutations in their DNA. the end result of these mutations of cellular control genes is that the cell now begins to receive instructions that cause its behavior to change from well controlled normal cells to that of an uncontrolled cancer cell.

Over the past 20 years, our understanding has increased dramatically regarding the changes that occur in these sets of instructions between cancer and normal cells. Until recently scientists have not been able to view simultaneously the impact of the drug or chemical on the activity of the overall set of instructions that the cell uses to regulate its behavior. Cancer cells in humans have a redundancy of mechanisms for maintaining their most important biological functions such as cell growth and replication.

Recently, new technologies such as microarray analyses have become available which can simultaneously evaluate the thousands of instructions that are present in normal and cancer cells. If a cancer cell is able to alter its instructions and thereby its behavior and in doing so escape the effect of a given therapeutic treatment, we are at least in a position to identify its new instructions and these new instructions can become the targets of new therapeutic agents and treatments.