The present invention provides a polypeptide or a pharmacologically acceptable salt thereof comprising one or more, identical or different, amino acid sequences of A-W--H--X1-D-X2-X3-X4-W--W--X5-X6-X7-X8-B (the meaning of each symbol in the formula is defined in the description) and a pharmaceutical composition for treating an angiogenic disease such as a solid tumor comprising said polypeptide. The present invention also relates to a polynucleotide encoding the above-mentioned polypeptide and use of the polynucleotide in gene therapy.