Skin Cancers

Cancer is a group of over 100 diseases characterized by out-of-control cell growth in a part of the body. Abnormal cells outlive normal ones and divide into more abnormal cells. Unregulated growth usually leads to formation of tumors, lumps or masses that can be either benign (non-cancerous) or malignant (cancerous). In some cancers such as leukemia, cancer cells circulate and grow in other tissues. Sometimes, parts of solid tumours break off and travel to start new tumours elsewhere. When cancer cells spread, the process is called metastasis.

Normally, each cell in the body grows, divides and dies in a cycle directed by the DNA in its nucleus. Any damaged DNA is repaired, or the cell dies. Cancer cells result when a cell survives despite damaged DNA. Damaged genes can be inherited, or DNA can be compromised by environmental factors such as chemicals, viruses, tobacco smoke or sunlight.

Skin cancers start in the cells of the epidermis, the outermost layer of skin. Below the epidermis are the dermis and subcutis, where blood vessels, nerves, sweat, oil glands and hair follicles are found. Three types of cells make up the epidermis:

Basal cells: new, round cells made deep in the epidermis.
Squamous cells: also called keratinocytes, formed by old basal cells, which flatten as they are pushed toward the skin surface by new basal cells.
Melanocytes: cells found between basal cells; they produce the skin-colouring pigment melanin.

Skin cancers are generally grouped as non-melanoma skin cancers (basal cell and squamous cell cancers) and melanoma.

To find more support and information about your skin condition, see the Basal Cell Carcinoma Nevus Syndrome/Gorlin Syndrome (BCCNS Life Support Network) or the American Melanoma Foundation.