Disclosed are compositions comprising polymeric nanoparticles and methods of using the same. The polymeric nanopartides can be conjugated with a targeting ligand that is a substrate for a solid tumor-specific cell protein. The polymeric nanoparticles can also comprises an imaging compound and/or a therapeutic agent encapsulated in the hydrophobic interior of the nanoparticle. A cancer therapeutic composition comprising the nanoparticle is also disclosed. The disclosed nanoparticles can be used to target and deliver imaging and/or therapueitc compounds to cancer cells, thereby identifying and/or treating a solid tumor cell target. Methods for treating cancer, such as lung cancer, using the polymeric nanoparticles are also disclosed.