Melanoma is a cancer that usually starts in the skin.
The different things the skin does include:
- protecting the body from injury
- protecting the body from the harmful effects of ultraviolet (UV) light
- keeping bacteria or viruses from getting into the blood and causing infections
- keeping fluids and proteins in the body
- controlling the body’s temperature
- giving us our sense of touch, through nerve endings, to feel and react to pain, heat or pressure
- helping the body make vitamin D (when skin is exposed to the sun) which is important to keep our bones healthy
- providing the skin with its colour.
Layers of the skin
The skin has different layers. There are 2 main layers that cover a fatty layer underneath.
This is the thin outer layer of the skin. The epidermis contains 3 types of cell:
- squamous cells – flat cells on the surface of the skin that are always shedding
- basal cells – rounder cells that are found under the squamous cells
- melanocytes – the cells that melanoma starts from, found in between the basal cells.
This is the inner layer of skin and is much thicker than the epidermis. It contains nerve endings, blood vessels, sweat glands and lymphatic vessels. It provides the epidermis with nutrition.
The hypodermis (fatty layer)
This is the fatty layer. It is the supportive layer of the skin and protects the body against cold. There are blood vessels and nerves in the dermis.
Melanocytes are cells that make a pigment called melanin. Melanin gives our skin, hair and eyes their colour. It also protects skin from the harmful effects of the sun.
When skin is exposed to sunlight, the melanocytes make more melanin. This is to absorb more of the harmful UV rays from the sun. This makes the skin look darker, or suntanned. A suntan is a sign that the skin is trying to protect itself.
If you have black or brown skin, you have the same number of melanocytes as people with white skin. But your melanocytes make more melanin. This means you have more natural protection from UV rays.
Moles are a group or cluster of melanocytes that are close together. They are sometimes called naevi.
Below is a sample of the sources used in our melanoma information. If you would like more information about the sources we use, please contact us at email@example.com
Michielin O, van Akkooi ACJ, Ascierto PA, et al. Cutaneous melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2019; 30, 12, 1884-1901 [accessed May 2022].
Michielin O, van Akkooi ACJ, Ascierto PA, et al. ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee. Annals of Oncology. 2020; 31, 11, 1449-1461 [accessed May 2022].
Peach H, Board R, Cook M, et al. Current role of sentinel lymph node biopsy in the management of cutaneous melanoma: A UK consensus statement. Journal of Plastic, Reconstructive & Aesthetic Surgery. 2020; 73, 1, 36-42 [accessed May 2022].
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Samra Turajlic, Consultant Medical Oncologist.
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