| CPC C07K 16/2818 (2013.01) [A61P 35/00 (2018.01); C07K 2317/52 (2013.01); C07K 2317/567 (2013.01)] | 10 Claims | 
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               1. A method of treating a tumor, wherein the method comprises administering a CTLA4-binding protein to a subject in need thereof, 
            wherein the CTLA4-binding protein comprises an antibody Fc domain and an antibody heavy chain variable region, and the antibody heavy chain variable region is directly or indirectly fused with the antibody Fc domain; and 
                wherein the heavy chain variable region comprises an amino acid sequence as set forth in any one of SEQ ID NOs: 8 and 17-20, and the antibody Fc domain is of human IgG1 isotype subtype. 
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