People with Most Moles are Most Likely to Develop
Deadly Melanoma Cancer, Study Finds
Already well known that people with red hair, fair
skin and those who sunburn easily are most at risk of melanoma
People with lots of moles should look for one that stands out in
the crowd.
July 6, 2009 Studies of massive numbers of people
in Europe and Australia has found that people with the greatest number
of moles are the people most likely to develop the most dangerous form
of skin cancer, melanoma, which is on the increase. Around 48,000 people
worldwide die of melanoma each year, which is most common in older males
and those with pale skin.
The study, led by Professors Julia Newton Bishop
and Tim Bishop of the Melanoma Genetics Consortium (GenoMEL) at the
University of Leeds, looked at more than 10,000 people, comparing those
who have been diagnosed with melanoma to those who do not have the
disease.
Couples encouraged to examine each other for
suspicious moles that could be skin cancer. Researchers estimate that 40
50% of people in the U.S. who live to age 65 will have nonmelanoma
skin cancer at least once.
Researchers across Europe and in Australia, looked
at 300,000 variations in their research subjects' genetic make-up, to
pinpoint which genes were most significant in developing melanoma a
disease which causes the overwhelming majority of skin cancer related
deaths. Their findings are published in the journal Nature Genetics.
Across the large sample, a number of clear genetic
patterns emerged.
It is already well known that red-haired people,
those with fair skin and those who sunburn easily are most at risk of
melanoma, and the people who had been diagnosed with melanoma were found
to be much more likely to be carrying the genes most closely associated
with red hair and freckles.
"This is what we expected to find," said Professor
Bishop of the Leeds Institute of Molecular Medicine and the Cancer
Research UK Centre at Leeds. "But the links seemed to be much stronger
than we anticipated."
"We had known for some time that people with many
moles are at increased risk of melanoma. In this study we found a clear
link between some genes on chromosomes 9 and 22 and increased risk of
melanoma. These genes were not associated with skin color," he added.
About Melanoma
Melanoma is the most
serious type of
skin cancer. Often the first sign of melanoma is a change in the
size, shape, color or feel of a mole. Most melanomas have a black or
black-blue area. Melanoma may also appear as a new mole. It may be
black, abnormal or "ugly looking."
Melanoma can be cured if
it is diagnosed and treated early. If melanoma is not removed in its
early stages, cancer cells may grow downward from the skin surface and
invade healthy tissue. If it spreads to other parts of the body it can
be difficult to control.
"Instead, in joint research with colleagues at
King's College London and in Brisbane who counted the number of moles on
volunteer twins, we showed that these genes actually influenced the
number of moles a person has."
It is widely believed that the increase in
melanomas is largely due to social and behavioral activities, such as
increased exposure to the sun, partly caused by the availability of
cheaper foreign holidays. Sunny holidays increase the risk because it is
intermittent sun exposure which causes melanoma rather than daily
exposure over longer periods of time.
Even so, the process by which sunlight and genetics
combine to cause cancer in some people, is still poorly understood, as
Professor Bishop explained:
"If you take the people who have the greatest
exposure to sunlight those who work outside for example and compare
them to those with the least exposure, their risks of getting skin
cancer are actually quite similar. Statistically, the differences are
quite negligible.
"What we do know is that the combination of
particular genes and a lifestyle of significant sun exposure is putting
people at greatest risk."
The research shows that there are at least five
genes which influence the risk of melanoma. A person carrying all the
variants associated with an increased risk is around eight times more
likely to develop melanoma than those carrying none, though the majority
of people carry at least one of these variants.
"The more we can understand malignant melanoma
through research like this the closer we should get to controlling what
is an often fatal cancer, said Sara Hiom, Cancer Research UK's director
of health information.
This study confirms Cancer Research UK's advice in
its SunSmart campaign that people with lots of moles as well as those
with red hair and fair skin are more at risk of the most dangerous
form of skin cancer and should take extra care in the sun.
"The research goes further and identifies the
actual genes associated with this increased risk."
For advice on moles, please see the Patient
Information Section (Click
Here)
Moles are normal, but people should seek the advice
of their doctor if a mole changes in shape, size or color or for
anything new which looks different to other marks on the skin,
particularly if it changes over time.
Melanoma is one of the rarer types
of skin cancer but causes the majority of skin cancer related
deaths.More at
Wikipedia
Background Information
1. The paper Genome-wide association study
identifies three loci associated with melanoma risk, is published in
Nature Genetics.
2. Tim Bishop is Professor of Genetic Epidemiology,
and Julia Newton-Bishop is Professor of Dermatology, in the Leeds
Institute of Molecular Medicine at the University of Leeds.
3. The 2008 Research Assessment Exercise showed the
University of Leeds to be the UK's eighth biggest research powerhouse.
The University is one of the largest higher education institutions in
the UK and a member of the Russell Group of research-intensive
universities. The University's vision is to secure a place among the
world's top 50 by 2015.
www.leeds.ac.uk
4. The Leeds Institute of Molecular Medicine (LIMM)
is a research Institute of the University dedicated to defining the
molecules involved in human diseases, and using this knowledge to
develop novel therapies and new drugs.
www.limm.leeds.ac.uk/
5. Research by the Melanoma Genetics Consortium (GenoMEL)
at Leeds brings together world-class expertise and a range of different
disciplines to halt the rise of skin cancer. GenoMEL's focus is on
genetics in relation to the incidence of melanoma, with a multi-national
grouping of 23 different research capturing research and data from a
range of latitudes, populations and climates.
www.genomel.org/. GenoMEL is coordinated by the University of Leeds.
