OUTLINE: This is a dose escalation study. Patients are assigned to one of three treatment groups. Group I: Patients receive particle mediated gene transfer (PMGT) of gp100 on day 1 to 2 or 4 separate sites. One site is biopsied on day 3. A second course is administered on day 22 and one of the sites is biopsied on day 26. Delayed type hypersensitivity (DTH) is assessed on days 40 and 43. Group II: Patients receive PMGT of sargramostim (GM-CSF) on day 1 to 1-5 separate sites. PMGT of gp100 is administered to 2-4 of these same sites on day 4. One of the gp100 sites is biopsied on day 6. A second course is administered beginning on day 22, with one of the sites biopsied on day 29. DTH is assessed on days 40 and 43. Group III: Patients receive PMGT of GM-CSF in combination with gp100 on day 1 to 2 or 4 separate sites. Courses are administered as in group I. Patients who achieve partial or complete response or maintain stable disease may receive another course of therapy. Cohorts of 3-6 patients are treated at each dose in each group until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose limiting toxicity. Patients are followed at 3, 6, and 12 months, and then annually thereafter.