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What causes melanoma?

The main cause of all types of skin cancer is overexposure to ultraviolet (UV) radiation.

UV radiation most often comes from the sun, but it can also come from artificial sources such as solariums (also known as tanning beds or sun lamps). Solariums are now banned for commercial use in Australia because research shows that people who use solariums have a much greater risk of developing melanoma.

Anyone can develop melanoma. The risk is higher in people who have:

  • unprotected exposure to UV radiation, particularly a pattern of short, intense periods of sun exposure and sunburn, such as on weekends and holidays
  • lots of moles (naevi) – more than 10 moles above the elbow on the arms and more than 50 on the body, especially if the moles have an irregular shape and uneven colour (dysplastic naevi)
  • pale, fair or freckled skin, especially if it burns easily and doesn’t tan
  • light-coloured eyes (blue or green), and fair or red hair
  • a previous melanoma or other type of skin cancer
  • a strong family history of melanoma
  • a weakened immune system from using immunosuppressive medicines for a long time (e.g. for rheumatoid arthritis or another autoimmune disease or after an  organ transplant).

Why is sun protection important?

When your unprotected skin is exposed to the sun or other UV radiation, the structure and behaviour of the cells can change. This can permanently damage the skin, and the damage adds up over time.

Being exposed to too much UV radiation as a child increases the risk of skin cancer later in life, although sun protection will help prevent melanoma at any age. 

Family history of melanoma

Sometimes melanoma runs in families. Often, this is because family members have a similar skin type or a similar pattern of sun exposure in childhood.

Only 1–2% of melanomas in Australia involve an inherited faulty gene. Some of these genes have been identified.

If two or more close relatives (parent, sibling or child) have been diagnosed with melanoma, they may have an inherited faulty gene. This is especially the case if they are diagnosed with more than one melanoma on different areas of the skin, or if they are diagnosed with melanoma before the age of 40.

People with a strong family history of melanoma should protect and monitor their skin themselves, and have a professional skin check by a doctor every year from their early 20s. New moles or skin spots after this age should be investigated.

If you are concerned about your family risk factors, talk to your doctor about having regular skin checks or ask for a referral to a family cancer clinic. Visit genetics.edu.au to find a family cancer clinic near you. To find out more, call Cancer Council 13 11 20.

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This information is reviewed by

This information was last reviewed January 2021 by the following expert content reviewers: A/Prof Robyn Saw, Surgical Oncologist, Melanoma Institute Australia, The University of Sydney and Royal Prince Alfred Hospital, NSW; Craig Brewer, Consumer; Prof Bryan Burmeister, Radiation Oncologist, GenesisCare Fraser Coast and Hervey Bay Hospital, QLD; Tamara Dawson, Consumer, Melanoma & Skin Cancer Advocacy Network; Prof Georgina Long, Co-Medical Director, Melanoma Institute Australia, and Chair, Melanoma Medical Oncology and Translational Research, Melanoma Institute Australia, The University of Sydney and Royal North Shore Hospital, NSW; A/Prof Alexander Menzies, Medical Oncologist, Melanoma Institute Australia, The University of Sydney, Royal North Shore and Mater Hospitals, NSW; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Paige Preston, Chair, Cancer Council’s National Skin Cancer Committee, Cancer Council Australia; Prof H Peter Soyer, Chair in Dermatology and Director, Dermatology Research Centre, The University of Queensland Diamantina Institute, and Director, Dermatology Department, Princess Alexandra Hospital, QLD; Julie Teraci, Clinical Nurse Consultant and Coordinator, WA Kirkbride Melanoma Advisory Service, WA.