DISEASE CHARACTERISTICS: Clinically dysplastic nevi with a personal history of cutaneous melanoma and/or a family history of cutaneous melanoma in two or more blood relatives (blood relatives include first, second, or third degree relatives from the same blood line) Clinically dysplastic nevi defined as: At least 4 mm in diameter and flatness (either a component or throughout) with at least 1 of the following: Variable pigmentation Irregular or asymmetrical outline Indistinct border Must have at least 10 or more large (diameter at least 4 mm) clinically dysplastic nevi on the trunk or extremities (excluding head, pubic area, breasts in women, hands, and/or below the knees) No stage III or IV melanoma Patients with history of melanoma who received adjuvant therapy must be more than 1 year from completion of therapy