Study shows risk of melanoma can be detected before appearance of moles
THE risk of developing melanoma, a deadly skin cancer, can be estimated long before detection of any suspicious moles, new research suggests.
Skin damage from the sun builds up over time but is not always obvious to the eye.
However, DNA within skin cells also accumulates damage over years of exposure to the sun’s ultraviolet rays and this damage can be measured, according to a new study.
The research suggests the genomic methods used to probe skin damage could be developed to estimate baseline melanoma risk.
They could also be used to make recommendations about how often someone should be screened for cancer by a dermatologist.
Hunter Shain, assistant professor at the University of California, San Francisco’s department of dermatology, said: “A multitude of individual cells in so-called normal skin are riddled with mutations associated
with melanoma, which are a result of sun exposure.
“Melanoma is an endpoint most often seen only after decades of mutational damage, but some people are at greater risk.
“With the techniques we have developed, those who have the most accumulated mutations can be monitored more closely.”
Melanoma arises in a type of skin cell called a melanocyte. These cells make the pigment melanin, which helps protect skin cells, including the more abundant keratinocytes, from sun damage.
But melanocytes pose the greatest risk when DNA damage causes them to grow out of control.
In the study, published in Nature, researchers sequenced melanocyte DNA in skin samples, one cell at a time, to tally mutations, with an emphasis on a handful of mutations that are the main drivers of the emergence and growth of melanoma.
The samples came from six individuals, two melanoma survivors and the cadavers of four people who had never had melanoma. All of the people were white.
They found that melanocytes from normal skin near the melanoma in the former cancer patients had strikingly more mutations, including melanoma-associated mutations, than skin from the same sites in individuals who never had melanoma.
Prof Shain said people with many moles should still be screened, but only 30pc of melanomas arise from preexisting moles.