This is an open-label study of ZYC300 in the treatment of advanced stage malignancy of the kidney in patients who have not had previous immune-based therapies or treatment of advanced stage malignancies (cancerous growths) of the ovary, breast, colon, or hormone-refractory prostate in patients who have failed at least one but no more than two prior regimens of chemotherapy. Patients who meet all entry criteria will be administered 600 mg/m^2 cyclophosphamide intravenously 3 days before each dose of ZYC300. ZYC300 will be administered at 400 micrograms DNA/total dose every two weeks for a maximum of six doses (6 cycles).