Decreased expression of prostatic secretory protein PSP94 in prostate cancer

cDNA libraries were generated from the prostate gland tissue obtained from a normal donor and from a patient with prostate cancer. Subtractive cDNA cloning was used to identify phenotype-specific cDNA sequences from both normal and cancerous prostate tissue. One clone, pN44, isolated from normal prostate tissue, codes for the prostate protein PSP94, expression of which appeared to be down-regulated in the cancerous cells. Rabbit antisera against PSP94 were generated, and these antisera can be used to detect PSP94 in urine. Two other clones, pN23a and pN141f, were also found to be down-regulated.