CORRESPONDENCE

Re: Antiangiogenic Activity of Prostate-Specific Antigen

Masood A. Khan

Correspondence to: Massod A. Khan, M.D., Royal Free Hospital School of Medicine, Department of Urology, Pond St., London NW3 2QG, U.K.

Although prostate-specific antigen (PSA) has been shown by Fortier et al. (1) to inhibit endothelial cell proliferation, migration, and invasion as well as metastatic spread, the value of these findings has to be questioned. This skepticism is due to the fact that, in all the experiments carried out, very high concentrations of PSA—equivalent to many thousands of ng/mL—were used. These high concentrations are very uncommon in humans, since the vast majority of men with prostate cancer have PSA levels well below 1000 ng/mL (2-4). More importantly, patients will experience symptomatic metastatic disease at PSA levels that are a fraction of those used in the experiments carried out by the authors (5-7). Hence, it is difficult to state whether, in the vast majority of patients with prostate cancer, PSA has any antiangiogenic or antimetastatic properties. It would have been far more informative if the authors had used concentrations of PSA that more closely reflect the levels detected in patients with prostate cancer. Without this information, it is too speculative to consider that elevations of PSA may be a defense against cancer progression and that the administration of PSA may be a rational therapeutic approach in the treatment of prostate cancer.

REFERENCES

1 Fortier AH, Nelson BJ, Grella DK, Holaday JW. Antiangiogenic activity of prostate-specific antigen. J Natl Cancer Inst 1999;91:1635-40.[Abstract/Free Full Text]

2 Sassine AM, Schulman C. Clinical use of prostate-specific antigen in the staging of patients with prostatic carcinoma. Eur Urol 1993;23:348-51.[Medline]

3 Pons-Anicet D, Ramaioli A, Namer M, Krebs BP. Evaluation of prostate-specific antigen in prostate cancer. Am J Clin Oncol 1988;11:S71-4.[Medline]

4 Guillet J, Role C, Duc AT, Francois H. Prostate-specific antigen (PSA) in the management of 500 prostatic patients. Am J Clin Oncol 1988;11:S61-2.[Medline]

5 Wu TT, Chen KK, Huang JK, Lee YH, Chen MT, Chang LS. Prediction of lymphatic spreading in prostatic cancer by prostate-specific antigen and Gleason's score. Eur Urol 1994;26:202-6.[Medline]

6 Sands ME, Zagars GK, Pollack A, vonEschenbach AC. Serum prostate-specific antigen, clinical stage, pathologic grade, and the incidence of nodal metastases in prostatic cancer. Urology 1994;44:215-20.[Medline]

7 Wolff JM, Bares R, Jung PK, Buell U, Jakse G. Prostate-specific antigen as a marker of bone metastasis in patients with prostate cancer. Urol Int 1996;56:169-73.[Medline]



             
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