A global collaboration of scientists has more than doubled the known number of regions on the human genome that influence the risk of developing melanoma.
Writing in the journal Nature Genetics, they say they have identified 33 new regions and confirmed another 21 previously reported regions that are linked to a person’s risk of developing the sometimes-deadly skin cancer.
The study, which brought together researchers and health professionals from 115 institutions around the world, was co-led by Australia’s QIMR Berghofer, the University of Leeds, UK, and the National Cancer Institute in the US.
“Two of the new regions we’ve discovered that are linked to melanoma have previously been linked to autoimmune disorders,” says QIMR Berghofer’s Matthew Law. “This provides further evidence that the immune system plays an important role in a person developing melanoma.
“We also found an association between melanoma and common genetic variants in the gene TP53, which is a gene critical in controlling DNA repair when cells divide, and in suppressing cancer.”
Melanoma begins in melanocytes, the cells in the skin responsible for making the pigment melanin that gives colour to the skin.
Melanin can block some of the harmful effects of UV radiation, which is why people with pale skin are at a higher risk of skin cancer, but the protection is not complete.
Moles also develop from melanocytes; having a high number of moles is a risk factor for melanoma.
The study examined DNA from 37,000 people who had been diagnosed with melanoma and compared their genetic information to that of nearly 400,000 people with no history of the disease.
“The large population sample made it possible to recognise which regions of the genome were active in people with melanoma,” says Mark Iles from the University of Leeds.
“The population sample we used is three times larger than any previous genetic study on melanoma risk and gives us strong confidence that the new regions we’ve discovered all play a role in the disease.
“It’s a product of power in numbers. The only way to discover these things is by having such a large study population that spans across the globe…”