or someone that you know may be affected by cancer or the
"enemy within." It is often asked what causes cancer
and how does cancer progress. Over the last two decades, there
have been great advances in our understanding of cancer's
causes and progression, and in particular, the genes that
affect cancer development. These achievements have led to
better tools to detect and treat cancers.
Cancer is the result of seemingly normal cells that acquire
molecular changes allowing the cancer cells to multiply wildly
with complete disregard for normal cues. Cancer cells that
escape and spread to other parts of the body eventually beat
down the body and cause death. What are the molecular changes
that contribute to cancer development?
Perhaps the best analogies for cancer genes and tumor suppressor
genes are car accelerators and brakes (See Figure). Normal
cells possess accelerators, genes that instruct cells to multiply,
and brakes or genes that keep normal cells from multiplying
excessively. The normal accelerators are termed proto-oncogenes
(precursors of oncogenes or cancer genes), which normally
regulates cells as they multiply during growth of a fetus
or to replace cells that are lost in adults. The brakes or
tumor suppressor genes provide a means to control the multiplication
of the cells so that they conform to the normal architecture
of tissues and organs. The coordination both accelerators
and brakes is extremely important for the cells to navigate
through the growth and development of a child or for the repair
of damaged tissues. If the brakes are lost and/or the accelerators
are stuck on the floor-board, then the cells would go out
of control and may result in abnormal multiplication of the
cells or tumor development.
this website, we chose to focus on the MYC cancer gene or
accelerator that contributes to more than 70,000 cancer deaths
annually in the US. The normal MYC gene is important for embryonic
development, such that its complete absence in the mouse causes
death of embryos. When the MYC accelerator is stuck, the MYC
gene is ON in cells at times when it is not supposed to be
ON. Normal cells respond to the stuck accelerator by hitting
hard on certain types of brakes or tumor suppressor genes.
The result is frequently a burned-out engine or cell suicide
termed "apoptosis." However, if the same cell that
contains a stuck accelerator is also one that had a defective
brake mechanism (loss of a tumor suppressor gene), the cell
would not undergo suicide but rather multiply erratically.
The result is a tumor that could well progress and spread
to other parts of the body.
The MYC cancer gene contains instructions for the production
of the c-Myc protein. The c-Myc protein is now known as a
transcription factor or a regulator of other genes. It is
a protein that binds DNA at specific sites and instructs genes
whether or not they should be transcribed into messages for
cells to make additional or other new proteins. This website
is designed for interested scientists to find information
regarding the role of MYC in human cancers and information
about the genes that are regulated by the c-Myc protein.
For additional information about cancers and cancer genes,
the reader can use the available links on this site to the
National Cancer Institute, The American Cancer Society, The
American Society of Hematology or The American Association
for Cancer Research.