They can develop from existing moles, but they more often appear as new marks on the skin, the charity says. This can appear anywhere on the body, but the most commonly affected areas are the back ...
BBC journalist Sarah Lee was diagnosed with stage three malignant melanoma in January, five months after three different doctors had dismissed her concerns about a new mole on her scalp.
Moles can appear anywhere on the body but are more common in areas exposed to the sun. The NHS website advice is to check your skin for any unusual changes, and see your GP if you notice any.