Melanocytes and Melanin
Melanocytes are cells located in the lower part of the epidermis, just above the dermis. They make the pigment called melanin, which gives color to the skin, hair, and parts of the eye.
Melanin protects the skin from ultraviolet (UV) radiation, the harmful rays of the sun.
Moles or Clusters of Melanocytes
A mole is a cluster of melanocytes that appears as a pigmented spot on the skin.
Moles can be either flat or raised, round or oval, and are usually smaller than a pencil eraser.
Although generally benign and unchanging, moles can sometimes become cancerous.
The first sign of melanoma is often a change in the size, shape, or color of an existing mole or the appearance of a new mole in adulthood. (See Moles and Other Lesions for more information.
Both light- and dark-skinned people have the same number of melanocytes. The differences in skin color are the result of differences in the amount of melanin and the size of the melanin "packets" that each melanocyte makes.
Eumelanin, the most plentiful of human melanin, is found in brown and black skin and hair.
People with more eumelanin are more likely to tan and to
be protected from UV radiation.
People with less eumelanin are more likely to freckle or burn.
Pheomelanin is a red-yellow pigment most often found in fair-skinned people with red hair. Some red-haired people appear to not have any moles, because theirs are pink to red, not brown.
Albinos are unable to produce normal quantities of melanin and so have reduced levels or an absence of pigment in their skin, hair, and eyes.
The first sign of melanoma is often a change in the size, shape, or color of an existing mole or the appearance of a new mole.
It is believed that people with fair skin who freckle or burn easily are at especially high risk of developing melanoma.