The invention provides microparticles or nanoparticles for treatment of tumors comprising: (i) a targeting agent to the tumor or the tumor environment； and (ii) at least one inducer that stimulates a desired immune response in the tumor environment, leading to tumor apoptosis, wherein components (i) and (ii) are non-covalently or covalently attached to the surface of said microparticles or nanoparticles. The targeting agent is an agent that recognizes and binds to an antigen, a receptor or other molecules found on the surface of tumor cells or in the tumor environment and are preferably antibodies.
