A polypeptide, selected from the group consisting of: a fragment of the N terminus of human endostatin, wherein the amino acid sequence of the human endostatin is set forth in SEQ ID NO: 1, having 45 or less amino acid residues, and containing at least amino acid residues 1 to 20 of the N terminus, and wherein amino acid residue at positions 2 and 18 of the N terminus of human endostatin are respectively selected from the combinations as shown below: Amino acid residue at position 2 Amino acid residue at position 18 A M R I N K D E, M, T or Y Q A or H E S or V H A or S L R, E or S K V M L or W F T P C or V T N, G, K, M, F, S or T w C, E, I, K, S or Y Y R, H, W or V V D or S and a fragment of the N terminus of human endostatin, wherein the amino acid sequence of the human endostatin is set forth in SEQ ID NO: 1, having 45 or less amino acid residues, and containing at least amino acid residues 1 to 20 of the N terminus, wherein the amino acid residue at positions 2 and 18 of the N terminus of human endostatin are respectively selected from the combinations as shown below: Amino acid residue at position 2 Amino acid residue at position 18 A M R I N K D E, M, T or Y Q A or H E S or V H A or S L R, E or S K V M L or W F T P C or V T N, G, K, M, F, S or T w C, E, I, K, S or Y Y R, H, W or V V D or S wherein the amino acid residue at position 17 of the N terminus of the human endostatin is S, A, L, I or T; and/or the amino acid residue at position 20 is S or T; and/or, if present, the amino acid residue at position 21 is G, A, L, I or V; and/or if present, the amino acid residue at position 22 is G, A, L, I or V. a fragment of the N terminus of human endostatin, wherein the amino acid sequence of the human endostatin is set forth in SEQ ID NO: 1, having 45 or less amino acid residues, and containing at least amino acid residues 1 to 20 of the N terminus, and wherein amino acid residue at positions 2 and 18 of the N terminus of human endostatin are respectively selected from the combinations as shown below: Amino acid residue at position 2 Amino acid residue at position 18 A M R I N K D E, M, T or Y Q A or H E S or V H A or S L R, E or S K V M L or W F T P C or V T N, G, K, M, F, S or T w C, E, I, K, S or Y Y R, H, W or V V D or S and a fragment of the N terminus of human endostatin, wherein the amino acid sequence of the human endostatin is set forth in SEQ ID NO: 1, having 45 or less amino acid residues, and containing at least amino acid residues 1 to 20 of the N terminus, wherein the amino acid residue at positions 2 and 18 of the N terminus of human endostatin are respectively selected from the combinations as shown below: Amino acid residue at position 2 Amino acid residue at position 18 A M R I N K D E, M, T or Y Q A or H E S or V H A or S L R, E or S K V M L or W F T P C or V T N, G, K, M, F, S or T w C, E, I, K, S or Y Y R, H, W or V V D or S wherein the amino acid residue at position 17 of the N terminus of the human endostatin is S, A, L, I or T; and/or the amino acid residue at position 20 is S or T; and/or, if present, the amino acid residue at position 21 is G, A, L, I or V; and/or if present, the amino acid residue at position 22 is G, A, L, I or V. wherein the amino acid residue at positions 2 and 18 of the N terminus of human endostatin are respectively selected from the combinations as shown below: Amino acid residue at position 2 Amino acid residue at position 18 A M R I N K D E, M, T or Y Q A or H E S or V H A or S L R, E or S K V M L or W F T P C or V T N, G, K, M, F, S or T w C, E, I, K, S or Y Y R, H, W or V V D or S wherein the amino acid residue at position 17 of the N terminus of the human endostatin is S, A, L, I or T; and/or the amino acid residue at position 20 is S or T; and/or, if present, the amino acid residue at position 21 is G, A, L, I or V; and/or if present, the amino acid residue at position 22 is G, A, L, I or V. <EOS>