The discovery of prostate-specific antigen.

The discovery of prostate-specific antigen (PSA) was beset with controversy; as PSA is present in prostatic tissue and semen, it was independently discovered and given different names, thus adding to the controversy. In this review we document the early research in this field to describe the chronology of the discovery of PSA. Using a comprehensive Medline search of the historical aspects of PSA, all relevant papers were reviewed; communication with the scientists involved in the discovery of PSA was an invaluable contribution. In 1960, Flocks was the first to experiment with antigens in the prostate and 10 years later Ablin reported the presence of precipitation antigens in the prostate. In 1971, Hara characterized a unique protein in the semen fluid, gamma-seminoprotein. Li and Beling, in 1973, isolated a protein, E1, from human semen in an attempt to find a novel method to achieve fertility control. In 1978, Sensabaugh identified semen-specific protein p30, but proved that it was similar to E1 protein, and that prostate was the source. In 1979, Wang purified a tissue-specific antigen from the prostate ('prostate antigen'). PSA was first measured quantitatively in the blood by Papsidero in 1980, and Stamey carried out the initial work on the clinical use of PSA as a marker of prostate cancer. Thus the discovery of PSA is interesting and surrounded by controversy. Although the credit for purifying PSA goes to Wang, other eminent scientists published research on this antigen. The initial work on PSA in semen was to asses its properties as a forensic marker for rape victims, but soon its potential as a marker for prostate cancer became evident.