The present invention relates to a novel protein, the Human Oncogene Induced Secreted Protein I ("HOIPS I") protein. In particular, isolated nucleic acid molecules are provided encoding the human HOIPS I protein. HOIPS I polypeptides are also provided as are vectors, host cells and recombinant methods for producing the same. Antibodies to human HOIPS I are also provided, as are diagnostic methods for detecting abnormal cell proliferation and differentiation disorders and therapeutic methods for treating the same.