Do not ignore warning signs. Have suspicious moles checked by a dermatologist. Melanoma is the deadliest form of skin cancer, but early diagnosis could save your life. If a mole appears abnormal, your doctor will do a biopsy by taking some of the mole tissue so it can be examined in a laboratory. Also, having a doctor check your moles once is not enough. Normal-looking moles can become cancerous later. Moles must be examined from time to time, especially if you notice any changes. If you have dysplastic nevi or if there is a history of melanoma in your family, you should have a physician check all of your moles regularly. Your physician will recommend how often you should have them checked.