The invention provides a new kind of tumor marker RL9/RL10 protein, the polynucleotide encoding the polypeptide, and the method of producing RL9/RL10 protein by recombinant technology. The invention also discloses the use of RL9/RL10 protein and the polynucleotides encoding RL9/RL10 protein, e.g., in diagnosing and treating tumor, as well as the pharmaceutical composition containing RL9/RL10 protein or the antibody against it.