Skin melanoma is a type of skin cancer that develops when melanocytes (the cells that give the skin its tan or brown colour) start to grow out of control. Exposure to ultraviolet radiation emitted naturally from the sun or from artificial sources such as tanning devices is the main cause of skin melanoma. The skin phenotype also plays an important role, with higher risk for fair-skinned persons. It is estimated that skin melanoma accounted for 4% of all new cancer diagnoses in EU‑27 countries in 2020 (all cancers, excluding non-melanoma skin cancers) and for 1.3% of all deaths due to cancer. This made it the sixth most frequently occurring cancer (after breast, colorectal, prostate, lung, and bladder cancers) and one of the 20 most frequent causes of cancer death.