Prostatic acid phosphatase (PAP), also prostatic specific acid phosphatase (PSAP), is an enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer or other diseases.The highest levels of acid phosphatase are found in metastasized prostate cancer. Diseases of the bone, such as Paget's disease or hyperparathyroidism, diseases of blood cells, such as sickle-cell disease or multiple myeloma or lysosomal storage diseases, such as Gaucher's disease, will show moderately increased levels.Certain medications can cause temporary increases or decreases in acid phosphatase levels. Manipulation of the prostate gland through massage, biopsy or rectal exam before a test may increase the level.Its physiological function may be associated with the liquefaction process of semen.