This invention is related to the use of an antisense oligonucleotide, comprising 8 to 30 nucleotide building blocks, which hybridizes with mRNA of TGF-beta 1, -2 and/or -3, VEGF, interleukin 10, c-jun, c-fos, MIA, and/or prostaglandin E2 for the preparation of a pharmaceutical composition for preventing and/or treating a tumor, wherein the antisense oligonucleotide is suitable to be administered intravenously in an amount of 400 to 800 mg/m2/treatment cycle.