Prostate-Specific Antigen: Chronology of Its Identification

I was pleased to read the timely update on prostate-specific antigen (PSA) by Drs. Jürgen Pannek and Alan W. Partin in the September 1997 issue of oncology (pp 1273-1278) and the accompanying review by Dr. Steven J. Jacobsen (pp 1281-1282). Dr. Jacobsen’s illustrated comparison of receiver-operator characteristic curves for PSA diagnosis in various settings was of particular interest and importance. However, the article by Pannek and Partin and another review of it by Dr. Gerald P. Murphy (pp 1283-1284) contain incorrect information regarding the historical chronology of the identification of PSA.

Dr. Murphy notes that we should not dwell on when and by whom PSA was identified, but “rather, we should focus on the significance of the finding.” Nonetheless, credit for the identification of PSA, should not be assigned incorrectly, as was done by Pannek and Partin and by Murphy. Although, I acknowledge the place of Hara et al[1] and Wang et al[2] in the historical chronology of this discovery, I also feel that those whose research established a priority deserve credit.

Roswell Park Studies Lead to PSA Identification
Dr. Murphy says further that it is “. . . important to recall where we were, not so very long ago.” He may then recall, during our respective days at Roswell Park Memorial Institute and the University of Buffalo (currently SUNY at Buffalo), our group’s immunologic studies on the prostate with the late distinguished professor Ernest Witebsky and the urological research conferences held at Roswell Park in the late 1960s. It was from these studies, which encompassed the identification of tissue-specific antigens of the normal and pathologic human prostate,[3-5] that PSA was initially identified.[3,4]

The observations made at that time,[3-5] including the seminal identification of PSA in 1970,[3,4], lay dormant until the report in 1979—9 years later—by Wang et al.[2] Many in the biomedical community have mistakenly accepted the latter report as the de novo identification of PSA. In confirming our group’s initial identification of PSA in the normal, benign, and malignant prostate,[3-5], Wang et al,[2] in essence, purified and characterized it.

Later Studies Confirm and/or Extend Initial Observations
In the interim between our initial studies in 1970[3,4] and those of Wang et al in 1979,[2] the studies of Hara et al in 1971[4], as well as Li and Beling in 1973[6] and Sensabaugh and Crim in 1978[7] (not cited by Pannek and Partin or by Murphy), have been variously credited with the identification of PSA. A review of these subsequent reports shows that they confirmed and/or extended our group’s initial observations.

Specifically, in reference to Hara et al,[1] who were credited by Pannek and Partin with the identification of PSA, I have read a translation from the Japanese of their work on g-seminoprotein. With the exception of the abstract of that study, which was published in English, how many investigators writing about PSA and citing Hara et al[1] have actually had the paper translated or were even able to obtain the paper, which appeared in the Japanese Journal of Legal Medicine in 1971? This was one year after our reports were published in the Journal of Reproduction and Fertility and the Journal of Immunology.[3,4] Irregardless, g-seminoprotein is of prostatic origin and is thus similar to the antigen that we found in the prostate, prostatic fluid, and seminal plasma.[3,4]

Conclusions
In conclusion, credit most certainly should be given to Wang et al,[2] for it was they who, in confirming and extending our initial observations,[3-5] subsequently purified and characterized PSA. Reviews on PSA by the late Dr. William H. Cooner[8] and by Partin and Oesterling[9] agree with this chronology. However, given Dr.  Partin’s previous accreditation of our initial identification of PSA,[9] the current review by Pannek and Partin is enigmatic.

References:

1. Hara M, Koyanagi Y, Inoue T, et al: Some physicochemical characteristics of gamma-seminoprotein: An antigenic component specific for human seminal plasma (in Japanese). Nippon Hoigaku Zasshi 25:322-324, 1971.

2. Wang MC, Valenzuela LA, Murphy GP, et al: Purification of a human prostate specific antigen. Investig Urol 17:159-163, 1979.

3. Ablin RJ, Soanes WA, Bronson P, et al: Precipitating antigens of the normal human prostate. J Reprod Fertil 22:573-574, 1970.

4. Ablin RJ, Bronson P, Soanes WA, et al: Tissue- and species-specific antigens of normal human prostatic tissue. J Immunol 104:1329-1339, 1970.

5. Ablin RJ: Immunologic studies of normal, benign, and malignant human prostatic tissue. Cancer 29:1570-1574, 1972.

6. Li TS, Beling CG: Isolation and characterization of two specific antigens of human seminal plasma. Fertil Steril 24:134-143, 1973.

7. Sensabaugh GF, Crim D: Isolation and characterization of a semen-specific protein from human seminal plasma: A potential new marker for semen identification. J Forensic Sci 23:106-115, 1978.

8. Cooner WH: PSA in a Clinical Setting. Eighth International Symposium on Transrectal Ultrasound in the Diagnosis and Management of Prostate Cancer, pp. 22-31. Rockville, American Institute of Ultrasound in Medicine, 1993.

9. Partin AW, Oesterling JE: The clinical usefulness of prostate specific antigen: Update 1994. J Urol 152:1358-1368, 1994.