Clinical, Laboratory, and Epidemiologic Characterization of Individuals and Families at High Risk of Melanoma

This study will investigate how genetic and environmental factors contribute to the development of melanoma, a type of skin cancer, and related conditions. Individuals \>=4 weeks with a personal or family history of melanoma or atypical spitzoid/Spitz tumor may be eligible for this study. Participants will: * Fill out one or two questionnaires about their personal and family medical history. * Provide written consent for researchers to review their medical records and pathology materials related to their care and those of deceased relatives with melanomas, tumors, cancer, or other related illnesses for whom they are the next-of-kin or legally authorized representative. * Donate a blood or cheek cell sample to be used for genetic studies. (The blood sample is collected through a needle in an arm vein. The cheek cell sample is obtained either by gently brushing the inside of the mouth with a soft brush or by swishing a tablespoon of mouthwash and then spitting it into a container.) * Undergo a skin biopsy (removal of a small piece of skin tissue) for genetic study. For this procedure, the area of skin to be removed is numbed with a local anesthetic and a 1/4-inch piece of skin is excised with a cookie cutter-like instrument. The wound is then covered with a band-aid. Participants may be asked to travel to the NIH Clinical Center for evaluation, including a medical history, physical examination, and some of the following procedures: * Full body skin examination to evaluate the type and number of moles and document any evidence of sun damage to the skin. The examination involves all the skin from the scalp to the bottoms of the feet. After the examination, a medical photographer will photograph the skin, with close-ups of skin lesions marked by the examiner. If there are parts of the skin the participant does not want examined or photographed, he or she can tell the examiner. * Blood draw of about 120 milliliters (4 ounces) or less * Skin biopsy * Cheek cell sample