May 17, 2017 Print
A new study has found that rarer forms of melanoma are not linked to UV radiation; an important discovery that will have a positive effect on preventing and treating these melanomas in the future.
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Professor Graham Mann, Dr Gulietta Pupo and Dr Varsha Tembe have discovered that rare melanomas are not caused by sun exposure.
A new study has found that rarer forms of melanoma are not linked to UV radiation; an important discovery that will have a positive effect on preventing and treating these melanomas in the future.
Lead author Professor Graham Mann from the Westmead Institute said the Australian Melanoma Genome Project found that melanomas on the hands and feet (known as acral) and internal surfaces such as the inside of lips (known as mucosal) have different causes to other skin cancers, which are traditionally linked to UV radiation.
“‘Slip, slop, slap’ is part of the Australian vernacular, but these less common melanomas are not caused by sun exposure like other skin cancers,” Professor Mann said.
The research team—including Dr Gulietta Pupo, Dr Varsha Tembe and Dr Sarah-Jane Schramm from the Westmead Institute—is the first in the world to study the entire DNA sequence of a large group of melanomas.
The study found acral and mucosal melanomas have much less gene damage compared with skin melanoma and the damage “footprints" did not match those of any known causes of cancer, like sun exposure.
Some mucosal melanomas unexpectedly had mutations in the SF3B1 and GNAQ genes, which had previously only been connected to melanoma of the eye.
Professor Mann said this important discovery has implications for preventing and treating these forms of melanoma.
“Acral and mucosal melanomas occur all over the world, but they have been even more challenging to treat than skin melanoma. They often behave more aggressively, are harder to diagnose, and have a poorer outcomes for patients.
“Knowing these are really different diseases to skin melanoma is important for development of future therapies. We must target new research to discover what is causing these cancers, and what can prevent them,” Professor Mann said.
“This is a world-leading genetic analysis of melanoma. We are working hard now to turn these discoveries into better results for melanoma patients,” Professor Mann concluded.
Every year in Australia, up to 420 people are diagnosed with acral or mucosal melanomas. They affect people of all ethnic backgrounds, and are the most common forms of melanoma in people with very dark skin.
The full research paper is available online in the Nature journal.
Background on melanoma
Melanoma is the most deadly of all skin cancers. Almost 14,000 Australians are expected to be diagnosed with melanoma in 2017; 2-3% of them will be diagnosed with acral and mucosal melanoma. The incidence of acral and mucosal melanoma is equal among different races, but it is the most common melanoma subtype in dark-skinned populations due to the rarity of skin melanoma.
Acral melanoma occurs on the soles of the feet, palms and nails (most commonly on the feet). Mucosal melanoma occurs in mucous membrane lining the respiratory, gastrointestinal and urogenital tract. Most mucosal melanomas originate in the nasal cavity and sinuses, oral cavity, anorectum, vulva and vagina.
Acral and mucosal melanomas are often diagnosed at an advanced stage as they are harder to detect. Treatment options are often less effective than for other forms of skin melanoma, so prognosis is often poor.