Moles and skin cancer
Researchers find if you have more than 100 moles on the body you run a high risk of developing skin cancer National Cancer Institute via Wikimedia Commons

A study has found a direct link between the number of moles in the arm and skin cancer, with more than 11 moles indicating an increased risk of the disease. Researchers say the findings could be used by doctors to establish whether an individual is prone to skin cancer or melanoma by counting moles on their body.

According to the study, published by experts from King's College London in the British Journal of Dermatology, if someone has more than 100 moles on their body, they have five times the normal risk of developing skin cancer.

"The findings could have a significant impact for primary care, allowing GPs to more accurately estimate the total number of moles in a patient extremely quickly via an easily accessible body part. This would mean that more patients at risk of melanoma can be identified and monitored," said lead author Simone Ribero of the department of twin research and genetic epidemiology at King's College.

In the UK, more than 13,000 people are affected by melanoma. Experts say if there are 11 moles on someone's right arm, s/he is likely to have more than 100 moles on their body which is a "strong predictor" of skin cancer.

"We demonstrated that arm mole count of more than 11 is associated with a significant risk of having more than 100 moles, that is in itself a strong predictor of risk for melanoma," the findings conclude.

The study was originally carried out on 3,584 female twins and was repeated on 400 men and women to find out more accurate results. Other factors including skin type and hair colour were also taken into account while undertaking the study, which was funded by the Wellcome Trust.

"But less than half of melanomas develop from existing moles. So it's important to know what's normal for your skin and to tell your doctor about any change in the size, shape, colour or feel of a mole or a normal patch of skin. And don't just look at your arms – melanoma can develop anywhere on the body, and is most common on the trunk in men and the legs in women," said Claire Knight, health information manager at Cancer Research UK.