OUTLINE: This is an open label, nonrandomized, single institution study. Patients receive 3 initial courses of treatment consisting of 21 days each. Treatment consists of an immunization with MAGE-3 or Melan-A peptide-loaded autologous PBMC and interleukin-12 (IL-12) on the first day, IL-12 on days 3 and 5, and 16 days of rest. The first cohort is not administered IL-12 and the next cohorts are given escalating doses of IL-12. The Phase II dose will be one dose level below the MTD. Patients who have a tumor remission response or stable disease may continue treatment for up to one year. Phase I completed as of 04/1999. Patients are followed every 3 months.