OBJECTIVES: I. Evaluate the immunologic and biologic activity of flt3 ligand (Flt3L) alone in patients with metastatic renal cell cancer or HLA-A2.1 negative melanoma.

II. Evaluate the immunologic and biologic activity of Flt3L alone or in combination with melanoma peptide immunization (MART-1, gp100:209-217, gp100:280-288, and tyrosinase) in patients with metastatic, HLA-A2.1 positive melanoma.

PROTOCOL OUTLINE: Patients are assigned to 1 of 3 treatment groups:

Group 1 (renal cell cancer): Patients receive Flt3 ligand (Flt3L) subcutaneously (SQ) alone on days 1-14.

Group 2 (HLA-A2.1 negative melanoma): Patients receive Flt3L SQ alone on days 1-14.

Group 3 (HLA-A2.1 positive melanoma): Patients may receive either Flt3L SQ alone on days 1-14 or in combination with melanoma peptide immunization. Patients may receive melanoma peptide immunization comprised of MART-1 immunodominant peptide, gp100:209-217, gp100:280-288, and tyrosinase peptide emulsified in Montanide ISA-51 SQ on day 12 of Flt3L administration.

Treatment repeats every 4 weeks for 2 courses. Patients with no response or minor response may receive 2 additional courses. Patients with disease progression after 1 course are removed from study.

PROJECTED ACCRUAL:

Approximately 54-96 patients (18-32 per treatment group) will be accrued for this study within 16 months.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics-- Histologically proven metastatic melanoma or renal cell cancer Patients receiving melanoma peptide immunizations must be HLA-A2.1 positive Measurable disease --Prior/Concurrent Therapy-- Biologic therapy: At least 1 month since prior biologic therapy Chemotherapy: At least 1 month since prior chemotherapy Endocrine therapy: No concurrent systemic steroid therapy At least 1 month since prior steroid therapy Radiotherapy: At least 1 month since prior radiotherapy Surgery: Prior surgery allowed Other: Greater than 1 month since prior therapy --Patient Characteristics-- Age: Not specified Performance Status: ECOG 0-1 Life Expectancy: Greater than 3 months Hematopoietic: WBC at least 3,000/mm3 Platelet count at least 90,000/mm3 No coagulation disorders Hepatic: Bilirubin no greater than 1.6 mg/dL AST and ALT less than 2 times normal Renal: Creatinine no greater than 2 mg/dL Cardiovascular: No major cardiovascular disease Pulmonary: No major pulmonary disease Other: Not pregnant or nursing Negative pregnancy test HIV negative Hepatitis B surface antigen negative No allergic reaction to Montanide ISA-51 No active systemic infection No prior autoimmune disorders