The two most common forms of skin cancer are basal cell carcinoma and the squamous cell carcinoma. The third most common form of skin cancer is melanoma, which starts in the melanocytes. There are other rare forms of skin cancer, such as those occurring in the sweat glands.

Exposure to ultraviolet (UV) radiation without protection measures - from the sun or other sources such as exposure to tanning machines - remains the most important risk factor for skin cancer. UV radiation is not visible and cannot be felt, but it can cause burns, premature skin ageing, skin damage that grows over time and can lead to skin cancer.

While skin cancer usually occurs in older people, the damage starts at a young age due to exposure to UV radiation, especially from sunburns. New research shows that while cells are often destroyed during childhood, sun exposure during adulthood may cause cells to mutate into cancerous cells.

We can all develop skin cancer. The risk increases if a person has many moles on their body, does not protect their skin from the sun, or spends a lot of time in the sun (e.g. outdoors at work), has a personal or family history of melanoma, is exposed to the sun periodically but for a long time (e.g. on holiday or during recreational activities), especially if this results in sunburn, has light skin with freckles that are easily irritated or difficult to tan, has red or blond hair and blue or green eyes, has spots or irregularly shaped moles, or has a weakened immune system.

People with dark or darker skin are more protected from skin cancer because they produce more melanin than people with lighter skin.

The best way to prevent skin cancer is to protect it from the sun. You can do this by learning the UV index, which shows the intensity of the sun's rays. When the UV index is 3 (moderate radiation) or above, the levels of solar radiation are high enough to cause skin damage and sun protection is necessary.

• Stay out of the sun between 11 am and 3 pm during the summer when the sun is strongest, and between 10 am and 2 pm the rest of the year. During these times of day, more than 60% of the sun's ultraviolet radiation reaches the earth's surface.
• Use the shade of trees, umbrellas, buildings or any kind of awning. Remember, UV radiation reflects off surfaces such as concrete, water or sand, causing you to burn, even when you think you are protected.
• Wear clothes that cover as many parts of the body and the back of the neck as possible. Fabrics with a dense weave give better protection. Wear a hat that shades your face, neck and ears.
• Use sunscreens with SPF 30+ that are both broad-spectrum and water-resistant, regardless of your skin type.
• Apply sunscreen 20 minutes before going out in the sun and repeat every two hours after swimming or any activity that makes you sweat or removes sunscreen.
• Protect your eyes with sunglasses. The more they cover the eyes, the better.
• Be sure to protect infants and young children from direct exposure to sunlight. Use shade, umbrellas, hats and clothing to protect them.
• If necessary, use SPF30+ sunscreen on unprotected areas of the skin, such as the face and upper arms.
• Do not use sunbeds and sun lamps, which emit UV radiation that increases the risk of skin cancer. Some sunlight is important for our health. When the skin is exposed to UV radiation, vitamin D is produced, which is essential for developing and maintaining strong and healthy bones. However, in order for your body to produce enough vitamin D to help you stay healthy, you don't need to be exposed to the sun for more than 10 minutes on most days of the week, except during times when UV radiation is high.

Get to know your skin and do a check four times a year, looking at your whole body including the soles of your feet, between your toes and your fingernails.

Use a mirror to check areas such as your back or the back of your legs. The signs to look for are: a new spot that is different from the other spots on the skin around it, a wound that won't heal, a scar, mole or blemish that has changed in size, shape or colour.

In this case, contact your dermatologist immediately. Your doctor will first look for the suspicious mark, mole or spot. If he suspects skin cancer, he will probably recommend a biopsy to confirm the diagnosis.

Biopsy is a quick and simple process. The doctor will give you a local anaesthetic and remove the lesion. Usually one or more stitches are done to allow the wound to heal. The tissue that has been cut will be sent to a lab, where the pathologist will examine it under a microscope. The results of the biopsy will determine what treatment is appropriate for your case. Often skin cancer is removed with the biopsy and no additional treatment is needed. If it is large or has spread beyond the surface of the skin, more tissue must be removed.