The present invention refers to immunosuppression-reverting oligonucleotides comprising 12 to 18 nucleotides, wherein at least one of the nucleotides is modified, and the oligonucleotide hybridizes with a nucleic acid sequence of an ectonucleotidase (NTPdase； CD73) of SEQ ID NO.1 (human), wherein the oligonucleotide inhibits at least 50% of the CD39 expression. The invention is further directed to a pharmaceutical composition comprising such oligonucleotide.
