Skin Cancer

As in actinic keratosis, the process starts with DNA damaged by UV that the cell's protective guardian genes, such as p53, can no longer repair. Over time, abnormal cells multiply without control. Think of the DNA as an instruction manual: each sunburn burns a few pages, and once the repair pages themselves are burned, a faulty cell keeps copying itself unchecked.

Basal cell carcinoma is the most common type. It arises from the basal layer of the epidermis, grows slowly, invades locally but very rarely spreads. It often appears as a small pearly or translucent bump, or a sore that does not heal or that bleeds, on sun-exposed skin. It is rarely fatal, but it is treated to avoid local damage.

Squamous cell carcinoma is the second most common type. It arises from more superficial keratinocytes, often from an existing actinic keratosis. It grows more quickly and carries a low but real risk of spreading if left untreated. It tends to appear as a rough, crusty patch that bleeds or develops into an open sore.

Melanoma is less common but the most dangerous type. It arises from melanocytes, the pigment-producing cells, and can spread if it is not caught early, which is why early detection is so vital. It can appear as a new mole or as an existing mole that changes in size, shape or colour.

The ABCDE rule is an educational self-check that helps you spot a possible melanoma. It does not replace a medical examination. A: Asymmetry, one half unlike the other. B: Border that is irregular or jagged. C: Colour that varies within one spot. D: Diameter, often larger than 6 mm. E: Evolving, any change, or a spot that bleeds or itches. Also watch for a sore that will not heal and the 'ugly duckling' spot unlike the others.