List the risk factors for melanoma.

Risk factors for malignant melanoma may be divided into genetic factors, environmental factors, and the interaction between the two.

Genetic factors include past medical history of melanoma, familial medical history of melanoma in a first-degree relative, Fitzpatrick type I or II skin, large congential nevi, the presence of dysplastic (atypical) nevi, >50 benign nevi (>2 mm in size), xeroderma pigmentosum, and familial dysplastic mole syndrome (FDMS). In FDMS, which is defined as occurring in families with atypical nevi and two or more blood relatives with melanoma, the estimated prevalence of melanoma approaches 85% by age 48. It is noteworthy that variations in the melanocortin receptor 1 (MCR1) gene, which is a component of pigment diversity, also confer an increased risk of melanoma. Variants differ in their associations with melanoma and nonmelanoma skin cancer, but both red hair and non–red hair variants confer increased risk.


Environmental factors include intermittently high-intensity exposure of fair skin to UVA and UVB radiation (especially at a young age), sunburns, immune suppression, and residence in equatorial latitudes. Ephelides (freckles), which are a reflection of sun exposure, are associated with a two- to threefold increased risk of melanoma.

MacKie RM, Hauschild A, Eggermont AM: Epidemiology of invasive cutaneous melanoma, Ann Oncol 20(Suppl 6):vi1–vi7, 2009.