Genetic Testing for Melanoma has Limits
With the availability of genetic testing for
melanoma, the deadliest form of skin cancer, you may be wondering if
you should be tested. Many people say that if the results showed a
higher-than-average risk, they would do more to protect their skin.
Dermatologists caution that we should not rely on genetic testing
alone. Here’s why.
Result Does Not Change Dermatologists’ Recommendations
Long before genetic testing, dermatologists recommended the
Get regular skin cancer screenings
Learn how to perform skin self-exams and
examine your skin regularly
Protect your skin from the sun — and do not
use tanning beds or sun lamps
This advice does not change with the
availability of genetic testing for melanoma. That’s right. If
genetic testing shows an increased risk, your dermatologist will
recommend the above. If genetic testing does not indicate an
increased risk, your dermatologist will still recommend these
practices. No one is immune to developing skin cancer. The first two
practices help find skin cancers, including melanoma, early when
treatment is most effective. The latter reduces your risk of
developing skin cancer.
CDKN2A Gene Mutations Rare
Today’s commercially available genetic test for melanoma looks
for gene mutations (changes) on a single gene called CDKN2A. Having
these mutations increases a person’s lifetime risk of developing
melanoma by an estimated 67% to 76%.
While this may tempt you to have the test, it is important to know
that the likelihood of having these mutations is rare. Only about 1%
of patients who develop a single, primary melanoma test positive for
CDKN2A. As such, dermatologists typically recommend genetic testing
for a small group of patients who have other select risk factors.
Melanoma has Many Risk Factors
Having certain mutations on the CDKN2A gene is but one risk
factor. Many other risk factors increase the likelihood of
developing melanoma. Excessive sun exposure, a previous skin cancer,
having many moles or atypical moles, and a history of blistering
sunburns are a few. A person may have all of these and have a
negative CDKN2A test. If this is the case, the person’s still has a
greatly increased risk of developing melanoma.
Test Result Could Give False Sense of
If the result is negative, this could give you a false sense of
security. It is important to know that a negative test does not mean
that you will not develop melanoma. Only a small percentage of
people who develop melanoma have the CDKN2A mutations.
Research shows that lifestyle accounts for much of our
susceptibility to diseases. And experts agree that what causes
melanoma is complex.
This means that you still need to protect your skin from the sun and
avoid tanning beds. Regular screenings and skin self-exams are
More Research Needed
The commercially available genetic test for melanoma is helpful
for a select group of patients. Researchers continue to look for
other genes that may play a role in melanoma. They also are looking
at our SNPs, which is short for “single nucleotide polymorphisms.”
Called “snips,” these are slight variations in our DNA that create
our differences in appearance and how we develop diseases.
One variation that may increase our risk for melanoma is MDM2
SNP309. Studies of MDM2 SNP309, however, show differing results.
Another gene being studied is MC1R. One study found that people who
have dark hair, suntan easily, and carry a variant on the MC1R gene
have an increased risk of developing melanoma. Interestingly, this
same study found that people who had this MC1R variant and red or
blond hair did not have an increased risk of developing melanoma.
Recent genetic studies also uncovered the genes responsible for sun
sensitivity, red hair, and freckling. While dermatologists have long
known that people who have these characteristics have an increased
risk of melanoma, they did not know what genes caused this.
Further research may identify more genes that can contribute to
melanoma. Research also may lead to breakthroughs in the treatment
of advanced melanoma.
Risk Factors: Melanoma
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test reporting improves early detection intentions and practices in
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photoprotection following CDKN2A/p16 genetic test reporting and
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Firoz EF, Warycha M, Zakrzewski J et al. “Association of MDM2
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Hike Melanoma Risk Even in Those Who Tan Well.” News release
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content solely developed by the American Academy of Dermatology
testing for melanoma currently shows mutations on one
gene. While these mutations greatly increase the risk of
developing melanoma, the test cannot predict whether or
not a person will get melanoma nor can it diagnose