2. WHAT IS SKIN CANCER?

Skin Cancer is the most common form of cancer and arises from cell mutations in skin cells.  Skin cancers are classified according to the type of skin cell from which they originate. Classification of skin cancer is important as different types of skin cancers have different survival rates, different rates of progression and require different treatment and management protocols. 

There are three basic types of skin cells; basal cells, squamous cells and melanocytes. Basal cells are found in the bottom layer of the epidermis and develop as they push towards the surface of the skin into keratinocytes or squamous cells which form the visible layer of skin we all know.  DNA damage to either basal or squamous cells can lead to non-melanoma type skin cancers generally referred to as either basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). 

Melanocytes are predominately skin cells found towards the bottom of the epidermis.  Melanocytes produce a protein called melanin, the pigment in skin that produces our skin colour and protects us from Ultraviolet (UV) Rays.  Mutations in the DNA of melanocytes can lead to a cancer commonly referred to as Melanoma.

The distinction between melanoma skin cancers and non-melanoma skin cancers is extremely important as the two types of cancer behave very differently.  According to the American Cancer Society, non-melanomas account for 96% of all skin cancers and 21% of skin cancer deaths while melanoma accounts for 4% of all skin cancers and 79% of skin cancer related deaths2.

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