The immune system is able to recognize tumor antigens and this has been the basis for the development of cancer immunotherapies.The immune system can be instructed to recognize and attack tumor cells by means of vaccination strategies.One such strategy involves the delivery of tumor antigen as genetic material.Herewith we describe the use of RNA encoding tumor antigens for vaccination purposes in tumor settings.RNA has features that are interesting for vaccination.Upon transfection,the RNA has no possibility of integration into the genome,and the tumor translated proteins enter the intrinsic antigen processing pathway thus enabling presentation by MHC-I molecules.This can specifically activate cytotoxic CD8 T cells that can attack and kill tumor cells.RNA can be delivered as a naked molecule for vaccination purposes or can be used to transfect dendritic cells.The combination of RNA technology with dendritic cell vaccination provides a powerful tool for cancer immunotherapies.