Abstract: Nucleic acid compositions and methods of use in treating solid tumors are disclosed. The nucleic acid compositions include a plurality of nucleic acid plasmids. Each plasmid encodes a single protein, either a cytokine or an anti-tumor protein. Each composition includes a plurality of these nucleic acid plasmids that encode a combination of two or more cytokines, a combination of cytokines and anti-tumor proteins, a combination of anti-tumor proteins, or an anti-tumor protein. The nucleic acid compositions of the invention can be delivered locally to a solid tumor.