Abstract: A set of contiguous and partially overlapping cDNA sequences and polypeptides encoded thereby, designated as PS118 and transcribed from prostate tissue, is described. These sequences are useful for the detecting, diagnosing, staging, monitoring, prognosticating, preventing or treating, or determining the predisposition of an individual to diseases and conditions of the prostate, such as prostate cancer. Also provided are antibodies which specifically bind to PS118-encoded polypeptide or protein, and agonists or inhibitors which prevent action of the tissue-specific PS118 polypeptide, which molecules are useful for the therapeutic treatment of prostate diseases, tumors or metastases.