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DNA is the genetic material in each of our cells. It passes
along genetic information to the next generation, making children look
like their parents, for example. Along with information about hair
color, facial features, and other aspects of how we look, DNA also
contains information that tells the cells of our body how to grow and
how to perform the activities needed for life.
Ultraviolet (UV) radiation can damage DNA. Sometimes this
damage affects certain genes (segments of DNA with a specific function)
that control how and when cells grow and divide. If these genes do not
function properly, the affected cells may form a cancer.
Most UV radiation comes from sunlight, but some may come from
man-made sources such as tanning booths. Usually it's not clear exactly
when UV exposure causes DNA damage that might eventually lead to
cancer. Some of the damage may take place in the few years before the
start of the cancer. But much of it may be due to exposures that
happened many years earlier. Children and young adults often get a lot
of intense UV sun exposure that may not result in an actual cancer for
many years or even decades.
Scientists have found that the DNA of certain genes is often
damaged in melanoma cells. Most of these DNA changes are not inherited;
they are more likely the result of damage caused by sunlight. But there
is evidence that some people can repair their damaged DNA better than
others and are less likely to develop melanoma. In the future, better
understanding of the way these DNA changes lead to melanoma might be
used to help treat or even prevent this disease.
A mutation in the BRAF gene is found in many melanomas. This
change is not inherited; it seems to occur during the development of
the melanoma. Blocking the activity of this gene may someday help treat
some people with advanced melanoma.
In some families with inherited melanomas, gene mutations that
greatly increase the risk of melanoma are passed from one generation to
the next. Familial (inherited) melanomas most often have changes in
genes such as CDKN2A (also known as p16) and CDK4 that prevent them
from doing their normal job of controlling the growth of the cell.
Scientists reason that this leads to overgrowth and eventually cancer.
Although most moles never turn into a melanoma, some do.
Researchers have found some DNA changes that transform benign nevus
(mole) cells into melanoma cells. But it is still not known exactly why
some moles become cancerous or why having many moles or atypical
(dysplastic) moles increases your risk of developing melanoma.
Last Medical Review: 06/05/2008
Last Revised: 05/14/2009
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