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

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

(a) measuring levels of CSG in cells, tissues or bodily fluids from a patient; and

(b) comparing the measured levels of CSG with levels of CSG in a noncancerous control, wherein an increase of 2 times higher in measured levels of CSG from said patient versus said control is associated with the presence of cancer,

wherein said CSG comprises SEQ ID NO:2.

2. A method of imaging cancer in a patient comprising administering to the patient an antibody which specifically binds CSG comprising SEQ ID NO:2.

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