Prostatic acid phosphatase

(PAP) An enzyme that is normally present only in small amounts in the blood, but that may be found at higher levels in some patients with prostate cancer, especially if the cancer has spread beyond the prostate.

However, blood levels may also be elevated in patients who have certain benign prostate conditions or early stage cancer.

Although PAP was originally found to be produced by the prostate, elevated PAP levels have since been associated with testicular cancer, leukemia, and non-Hodgkin's lymphoma, as well as noncancerous conditions such as Gaucher's disease, Paget's disease, osteoporosis, cirrhosis of the liver, pulmonary embolism, and hyperparathyroidism.