Abstract. It is well known that the main cause of low anti-tumor immune response lays in the low antigen difference between normal and tumor cells. New approaches to enhance the specific and non-specific immune reactions were intensively studied during the last years. The discovery of tumor-assosiated (TAA) antigens started the modern era of oncoimmunology. The structure and/or expression level of these antigens was shown to be different from those of normal cells. Ineffective immune response of cancer patients could be explained by the low immunogenicity of TAA, the synthesis of immunosuppressive molecules, local expression of inhibitory molecules, disruption of lymphocyte regulatory functions, inability to present antigen, and weak contact with tumor surface antigens. Some TAA were identified, but yet it is not clear, which of them could be targeted in clinical setting. The research in oncoimmunology should help to develop the approaches to enhance TAA immunogenicity.
