This is an infographic from pathologyreport.org showing 5 common things that should be known about the Prostate Specific Antigen Assay.
Prostate specific antigen (PSA), was first discovered and purified in 1979 by the Wang et al. group. This discovery made a small splash in the scientific community until the work was expanded upon. The foundation laid down by the Wang et al. group proved to be fundamental and changed the history of prostate cancer. Quickly, groups started to investigate the protein and see if there is a correlation to prostate cancer. In 1980, the first PSA assay to was developed.
Following this invention, groups around the world started to improve and use this assay to look at the underpinnings of prostate cancer. Through the 1980’s groups started to look into why the levels of PSA were raised when a patient had cancer. Through numerous studies it was found out that PSA was also a protease that cleaved seminal vesicle proteins. Through further analysis of PSA, it was found out that this protease had a similar primary structure to serine proteases and kallikreins. Additionally, the experimental data showed that the activity of PSA was similar to trypsin and chymotrypsin. Finally, it was determined in the late 1980’s that PSA was a serine protease with kallikrein like enzymatic activity that was especially selective towards hydrophobic molecules. After the function of PSA was determined, the Peter et al. group proposed the accepted hypothesis that the PSA cleaves gel-forming proteins from the seminal vesicles. After the research was done in the labs explaining PSA, it made its way to clinicians and their patients (De Angelis et al.).
PSA was one of the diagnostic tools that physicians used that radically changed how to diagnose and treat prostate cancer. When the PSA assay was first used, it was thought to be an incredibly advantage towards treating and diagnosing prostate cancer. In the late 1980’s the assay was used and started to shift the paradigm concerning overall prostate cancer treatment and diagnosis. Many studies were carried out in the following decade demonstrating how useful PSA was as a diagnostic tool; especially when it was used in combination of other diagnostic tools such as ultrasound and digital rectal exams. Through these efforts, the FDA approved the PSA assay in 1994. Since its widespread use, the PSA assay has come under scrutiny since it was used for so many cases which resulted in false positives and overtreatment of patients (De Angelis et al.).
Even though PSA assay was viewed as an incredible success in the beginning, it quickly became apparent that the PSA assay was not as great as once thought. Through numerous recent studies, it appears PSA assays are not as accurate as once thought. Of those who have the PSA, only 40% of the time does the assay accurately predict a cancerous tumor. The other 60% of the time resulted in men receiving an unneeded biopsy. Since the PSA assay has it downfalls, researchers are starting to develop a replacement. Two current possibilities are looking at PCA3 gene expression and AMACR gene expression (De Angelis et al.).