Method of diagnosing, monitoring, staging, imaging and treating prostate cancer

1. A method for diagnosing the presence of prostate cancer in a patient comprising:

(a) determining levels of CSG in prostate cells or tissue or bodily fluids in a patient; and

(b) comparing the determined levels of CSG with levels of CSG in prostate cells or tissue or bodily fluids from a non-cancerous control, wherein an increase in determined levels of CSG in said patient versus said control is associated with the presence of prostate cancer,

wherein said CSG comprises the protein expressed by the nucleic acid comprising SEQ ID NO:7.

2. A method of imaging prostate cancer in a patient comprising administering to the patient an antibody which specifically binds a CSG comprising the protein expressed by the nucleic acid comprising SEQ ID NO:7.

3. The method of claim 2 wherein said antibody is labeled with paramagnetic ions or a radioisotope.