Moles can turn into cancerous melanomas so it's important you check your moles regularly and talk to your doctor if there is any sign of danger.

Follow this 4 step, A-B-C-D, guide when checking your moles and if any of the points are true, be sure to take appropriate action.

Asymmetry: If one half of the mole does not match the other half. A mole or birthmark that has skin growth which increases in size should be examined by a doctor.

Border: If the edge of the mole is ragged, notched or blurred. Moles with skin cancer may have uneven borders.

Color: If the mole is a mix of brown, black and tan rather than an even color you should ensure it is looked at by a doctor. A mole that appears red or blue should also be cause for concern.

Diameter: If the mole is larger than a pencil eraser (6 mm). An important sign of melanoma is a change in size.

Check your body thoroughly at least every three months and if you have quite a few moles be sure to keep an eye on any changes. If any of your moles stand out from the others or if a mole starts bleeding for no apparent reason you should always consult your doctor.

The good news is that there is a lot you can do to protect yourself from skin cancer, or to catch it early enough so that it can be treated effectively, so make sure you check yourself thoroughly and often.