Melanocytes will become melanoma when malignant melanosis occurs. Currently, the only evidence for the cause of skin melanoma is the excessive exposure to ultraviolet radiation. Ultraviolet rays can damage the skin cells of DNA and cause melanoma. UV rays in sunlight can burn the skin and induce DNA mutations, in which UVA and UVB can induce the occurrence of melanoma, but UVB is the main reason for the occurrence of melanocyte gene mutation.

In addition, UVA can inhibit certain functions of the immune system, thereby accelerating the formation of the tumor. If the melanoma cells can be discovered before it leave the skin and enter into the lymph nodes and other parts of the body, the patient's five-year survival rate can reach 91.5%. And if this cancer is found late, then the patient's five-year survival rate will be only 30% to 60%.