Exposure to ultraviolet (UV) light: Nearly 90% of melanoma can be related to exposure to natural sources of UV light (sunlight) as well as unnatural sources, such as tanning beds. However, sun exposure/UV light is not the only risk factor, especially for mucosal and uveal melanoma. People with fair skin, blonde or red hair, or blue or green eyes have greater risk of developing melanoma.
Weakened immune system: people with weakened immune system, such as organ transplant recipients who are on immune suppressive therapy, may have increased risk of melanoma.
Additional risk factors include having a large number of moles or dysplastic nevi, a family history (one or more first-degree relatives) or personal history of melanoma, as well as some inherited conditions such as xeroderma pigmentosum (XP) with impaired ability to repair UV damage, are at increased risk of developing melanoma.