Diagnosis of prostate cancer

1. A method for diagnosing prostate cancer in an individual, said method comprising:

(a) separating urine sediment from a soluble urine fraction of a urine sample obtained from an individual suspected of having prostate cancer;

(b) concentrating the soluble urine fraction by ultrafiltration to produce a soluble urine concentrate, wherein the volume of soluble urine concentrate is reduced at least 50% from the original urine volume,

(c) detecting the amount of RNA from each of heat shock 60 kDa protein 1 (HSPD1), inosine monophosphate dehydrogenase 2 (IMPDH2), PDZ and LIM domain 5 (PDLIM5), and UDP-N-acetylglucosamine pyrophosphorylase 1 (UAP1) in the concentrated soluble urine fraction;

(d) comparing the amount of each said RNA to a reference value for each said RNA, wherein said reference value is derived from the amount of each RNA in a corresponding sample from one or more individuals that do not have prostate cancer; and

(e) diagnosing said individual as having prostate cancer when the amount of said RNA is greater than said reference value for each RNA.

2. The method of claim 1 , wherein the ultrafiltration comprises filtration using a filter having a nominal molecular weight limit of not more than about 50,000 daltons.

3. The method of claim 1 , wherein the ultrafiltration comprises filtration using a filter having an nominal molecular weight limit of not more than about 3,000 daltons.

4. The method of claim 1 , wherein the soluble urine fraction produced by the ultrafiltration is cell-free.

5. The method of claim 1 , wherein the RNA is isolated from the soluble urine concentrate by solid phase extraction.

6. The method of claim 1 , further comprising detecting the amount of RNA encoding prostate cancer antigen-3 (PCA3) in the concentrated soluble urine fraction.

7. The method of claim 1 , wherein the amount of each said RNA present in the soluble urine fraction is determined by reverse-transcriptase PCR (RT-PCR).

8. The method of claim 7 , wherein the determination by RT-PCR is performed in real-time.

9. The method of claim 7 , wherein the Ct value is used to determine the amount of each said RNA.

10. The method of claim 1 , wherein the amount of RNA is normalized to the amount of a control gene RNA.

11. The method of claim 10 , wherein the control gene RNA encodes a gene selected from the group consisting of prostate-specific antigen (PSA), c-abl oncogene 1, receptor tyrosine kinase (ABL1), beta actin (ACTB), beta-2 microglobulin (B2M), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta glucuronidase (GUSB).

12. The method of claim 11 , wherein the control gene RNA encodes PSA or GAPDH.

13. The method of claim 10 , wherein the amount of each RNA is normalized to the amount of control gene RNA using the formula:

Normalized Diagnostic Gene Score=Ln(Diagnostic Gene/Control Gene).

14. The method of claim 1 , wherein the amount of each RNA is used to generate a single diagnostic score, wherein the single diagnostic score is compared against a reference value for the single diagnostic score in order to diagnose said individual.

15. The method of claim 14 , wherein the amount of each RNA is normalized to the amount of control gene RNA using the formula:

Normalized Diagnostic Gene Score=Ln(Diagnostic Gene RNA/Control Gene RNA).

16. The method of claim 15 , wherein the single diagnostic score is calculated as the sum of the individual Normalized Diagnostic Gene Scores.

17. The method of claim 16 , wherein the control gene RNA encodes PSA or GAPDH.

18. The method of claim 17 , wherein said reference value is between about 2.6 and about 5.0.

19. The method of claim 17 , wherein said reference value is about 2.6.

20. The method of claim 17 , wherein said reference value is about 5.0.