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.
Among these most common enzymatic tumor markers, only PSA is specific or sensitive enough to identify specific organ involvement related to cancer.
On the following slides, the biochemistry and clinical applications of PSA will be discussed in greater detail.
