People respond to the environment in different ways. Some may be born with genes that make them more likely to get this type of skin cancer. Each person has many ways to repair normal damage to their genes. Specific genes may affect the repair of sun damage. Other genes affect the way the skin itself reacts to the sun. We want to find out which genes have normal changes in them and lead to different responses to exposures, such as the sun. We also want to find out if sun habits are related to the way these genes work.