The most commonly used tumor markers with enzymatic activity are:
- Prostate-specific antigen (PSA)
- Prostatic acid phosphatase (PAP)
- Alkaline phosphatase
- Neuron-specific enolase
PAP was used for many decades as a screening tool for prostate cancer; however, elevated PAP is also associated with cancers of the bone and bone marrow and benign conditions of the prostate, bones, and parathyroid. Although it lacks specificity as a tumor marker, PAP does have utility in staging prostate cancer.
Only PSA is specific or sensitive enough to identify particular cancer-related organ involvement among these most common enzymatic tumor markers.
On the following slides, the biochemistry and clinical applications of PSA will be discussed in greater detail.
