What is Melanoma?
This page provides basic information about melanoma. More comprehensive information is available on the website of our parent organization, AIM at Melanoma.
Melanoma arises from uncontrolled growth occurring in melanocyte cells and is the third most common type of skin cancer, behind basal cell carcinoma and squamous cell skin cancer. The top layer of skin—the epidermis—comprises basal cells, squamous cells, and melanocytes. Transformation from a normal to a precancerous or cancerous state in any of these skin cell types is problematic.
Melanocyte cells produce a brown pigment called melanin that gives skin its tan or brown color. Melanin acts as a natural sunscreen to protect the deeper layers of the skin from ultraviolet (UV) radiation. If these cells grow out of control and become cancerous, the condition is called melanoma.
While millions of cases of basal cell carcinoma and squamous cell skin cancer are diagnosed each year in the U.S., an estimated 200,340 cases of melanoma were diagnosed in 2024. Of those, 99,700 cases were in situ (noninvasive)—meaning they are confined to the top layer of skin (the epidermis)—and 100,640 cases were invasive—meaning the tumor penetrated the skin’s second layer, the dermis. Of the invasive cases, 59,170 were men and 41,470 women.
Melanoma is dangerous because it is more likely to metastasize (spread) than other skin cancers. Melanocytes represent a more aggressive cell type compared to its neighboring skin cells. Invasive melanoma accounts for only about 1% of all skin cancers, but it is responsible for the majority of deaths from skin cancer.
