The most common warning sign of skin cancer is a change in the appearance of the skin, such as a new growth or a sore that will not heal.

The term “skin cancer” refers to three different conditions. From the least to the most dangerous, they are:

• basal cell carcinoma (or basal cell carcinoma epithelioma)
• squamous cell carcinoma
• melanoma

The two most common forms of skin cancer are basal cell carcinoma and squamous cell carcinoma. Together, these two are also referred to as nonmelanoma skin cancer. Melanoma is generally the most serious form of skin cancer because it tends to spread (metastasize) throughout the body quickly.

Another, much less common, type of skin cancer is called malignant melanoma. About 7,000 people in the UK are diagnosed with malignant melanoma each year. Melanoma behaves differently to basal cell and squamous cell carcinomas.