A parvovirus characterized by a CpG-enriched genome, wherein the genome contains at least 2 additional CpG inserts that are not present in the wild type genome is described as well as the use of said parvovirus, e.g., a parvovirus based on parvovirus H1, LuIII, Mouse minute virus (MMV), Mouse parvovirus (MPV), Rat minute virus (RMV), Rat parvovirus (RPV), Rat virus (RV), vectors based on the foregoing viral species, and/or cells capable of actively producing the foregoing viral species for the preparation of a pharmaceutical composition, e.g., for the treatment of cancer, preferably pancreas carcinoma, hepatoma or lymphoma.