Skin cancer. Abstract illustration of skin cancer caused by sunlight, showing a setting sun over a landscape" of human skin in section. Cancer cells (blue) are spreading through the epidermis (red) and dermis (yellow). Skin cancer is most common in the elderly, pale-skinned, and people who live in hot sunny climates. In Australia over half the population has had skin cancer by age 75. The condition shown here is malignant melanoma, a type of skin cancer caused by tumours of pigment prod- ucing cells in the epidermis. Malignant melanomas usually start in moles, and are caused by mutations induced by ultra-violet radiation in sunlight. They can be fatal if not treated early."