<；P>；PROBLEM TO BE SOLVED: To provide a treating and/or preventive agent of cancer useful for treatment and/or prevention of cancer. <；P>；SOLUTION: By the SEREX method using a canine spermary-originated cDNA library and serum of a cancer-carrying dog, a cDNA coding a protein bonding with antibody existing in serum originated from cancer-carrying organisms is obtained, and a polypeptide having a specific new amino acid sequence is prepared on the basis of the cDNA. The peptide is useful for treating and/or preventing cancer because it can involute a cancer already having occurred in an organism when it is administered to the organism. <；P>；COPYRIGHT: (C)2009,JPO&INPIT
