Chris Condron finds balancing sun and sex and avoiding sewage makes summer holidays a risky business
PEOPLE with many moles on their skin should follow the example of the tunnelling rodent and keep out of the sun. The genetics of "moley" skin could explain our susceptibility to some forms of skin cancer, according to research beingconducted by the Royal London School of Medicine.
The work, backed by the Imperial Cancer Research Fund, aims to discover if we have a genetic susceptibility to "moleyness", and whether this is the most significant factor determining the development of malignant melanomas.
"A mole is any brown lesion on the skin - they do not necessarily have to be raised. Moles arecollections of melanocytes, or melanin-producing cells, and it is the amount of melanin in the skin that controls the ability of the skin to tan," explains Veronique Bataille, of the ICRF team.
"When the melanocytes start to turn malignant, they grow and produce more melanin, causing the distinctive growth and darkening of the mole."
For a number of years, Celtic skin-types have in particular been warned about the risks of exposure to sunlight.
In the early 1990s, large population studies in the UnitedKingdom, the United States and Australia revealed that some families had a greater susceptibility to melanoma and that these families tended to have more moles.
"Deciding just who is overtly moley can be incredibly difficult though, because moles are very common in the natural population," Dr Bataille says.
Previous work suggested the risk of melanoma was 12 times higher for those with more than 100 moles, compared with those with fewer than ten.
"Melanoma families are more likely to be fair, and burn. But the strongest indicator of melanoma is the number of moles. It is a very, very strong link," she says.
The work, led by Tim Bishop at the ICRF in Leeds, investigates the idea that we are born with a genetic susceptibility to moleyness.
One hundred melanoma families from all over the UK were surveyed about their holidays, sunbed use, sunscreen usage, smoking habits, family history and exposure to sunlight in childhood.
They were then given a skin examination to see how fair, freckly and moley they were, and the results were compared with non-melanoma families.
"We have found that the melanoma families do have different skin, usually molier," Mr Bishop said.
"We are now looking at the genetic difference between grandparents, and then comparing this to the parents and children."
Thirteen families form the basis for this detailed study. Future work will focus on determining which genes make some people more susceptible to moles.
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