What is known?
Two pathways and risk factors for the development of melanoma have been proposed – the first related to long-term sun exposure and the second to a genetic susceptibility to develop large numbers of moles (also called “naevi”). These two pathways are thought to be associated with melanoma development on different body sites.
What is new?
This study of Australian and UK participants examined factors associated with the different modes of melanoma development. Questionnaire and genetic data from people diagnosed with their first invasive melanoma were compared to that of people without the disease.
Melanomas of the trunk and limbs were found to be more strongly associated with increased mole counts, while head and neck melanomas were more strongly related to long-term sun exposure. Fairer skin tone was more strongly associated with melanoma on the head, neck and limbs, than on the trunk. Some of these associations were found to differ between females and males. For example, freckles in childhood were more strongly associated with head, neck and trunk melanomas in females, compared to males.
Combined genetic susceptibilities were found to be associated with an overall increased risk of melanoma, but this association only differed by body site when specific genetic variants were considered.
What does this mean?
The findings from this study provide a better understanding of risk factors for development of melanoma on different body sites, including mole density, skin tone, and type of sun exposure history. Knowing these risk factors will allow better understanding of that person’s melanoma risk according to body site.
Contact: Joanne Aitken
Reference: Laskar R, Ferreiro-Iglesias A, Bishop DT, Iles MM, Kanetsky PA, Armstrong BK, Law MH, Goldstein AM, Aitken JF, Giles GG, Robbins HA, Cust AE, Australian Melanoma Family Study Investigators, Leeds Case-Control Study Investigators. Risk factors for melanoma by anatomical site: an evaluation of aetiological heterogeneity. British Journal of Dermatology. 2020. doi: 10.1111/bjd.19705.