Interleukin-12 Gene Therapy in Treating Patients With Skin Metastases

DISEASE CHARACTERISTICS: * Histologically confirmed solid malignancy * Surgically or medically incurable disease * No standard chemotherapy or radiotherapy exists for this disease * Tumor of at least 0.5 cm but no more than 2.5 cm infiltrating into or underlying the skin * Cutaneous metastases, subcutaneous metastases, or tumor-involved lymph nodes that are easily palpable PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-1 Life expectancy: * More than 3 months Hematopoietic: * WBC greater than 3,000/mm\^3 * Platelet count greater than 80,000/mm\^3 Hepatic: * Bilirubin less than 2.0 mg/dL Renal: * Creatinine less than 2.0 mg/dL Other: * HIV negative * No active infections requiring antibiotic, antiviral, or antifungal treatment * No other active malignancy * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 1 month since prior immunotherapy * No concurrent colony-stimulating factors Chemotherapy: * See Disease Characteristics * At least 1 month since prior chemotherapy Endocrine therapy: * At least 1 month since prior steroids (other than intermittent use as an antiemetic or topical agent) * No concurrent steroids Radiotherapy: * See Disease Characteristics * Prior radiotherapy to vaccine site allowed provided there is documentation of progressive disease Surgery: * See Disease Characteristics * No prior organ allografts Other: * No other concurrent antineoplastic therapy * No other concurrent investigational drugs