Prostatic acid phosphatase (PAP), also prostatic specific acid phosphatase (PSAP), is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

produced by the

prostate The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and phys ...

. It may be found in increased amounts in men who have

prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that su ...

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 Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands ( primary hyperparathyroidism) or as response to external stimuli (secondary hyperparathyroidis ...

, diseases of

blood cell A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), ...

s, such as

sickle-cell disease Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red ...

multiple myeloma Multiple myeloma (MM), also known as plasma cell myeloma and simply myeloma, is a cancer of plasma cells, a type of white blood cell that normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, ane ...

lysosomal storage disease Lysosomal storage diseases (LSDs; ) are a group of over 70 rare inherited metabolic disorders that result from defects in lysosomal function. Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other ...

s, such as

Gaucher's disease Gaucher's disease or Gaucher disease () (GD) is a genetic disorder in which glucocerebroside (a sphingolipid, also known as glucosylceramide) accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low ...

, will show moderately increased levels. Certain

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field an ...

s can cause temporary increases or decreases in acid phosphatase levels. Manipulation of the prostate gland through massage,

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a d ...

rectal exam Digital rectal examination (DRE; la, palpatio per anum, PPA) is an internal examination of the rectum, performed by a healthcare provider. Prior to a 2018 report from the U.S. Preventive Services Task Force, the DRE was a common and "dreaded" co ...

before a test may increase the level. Its physiological function may be associated with the liquefaction process of

semen Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen ...

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Use in prostatic cancer prognosis

Serum marker

PSAP was used to monitor and assess progression of

until the introduction of prostate specific antigen (PSA), which has now largely displaced it. Subsequent work, suggested that it has a role in prognosticating intermediate and high-risk prostate cancer, and led to renewed interest in it as a

biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, p ...

Immunohistochemistry

PSAP

immunohistochemical staining Immunohistochemistry (IHC) is the most common application of immunostaining. It involves the process of selectively identifying antigens (proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to a ...

is often used with PSA (staining), by

pathologist Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in t ...

s, to help distinguish poorly differentiated

carcinoma Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesoderma ...

s. For example, poorly differentiated prostate adenocarcinoma (

) and urothelial carcinoma (

bladder cancer Bladder cancer is any of several types of cancer arising from the tissues of the urinary bladder. Symptoms include blood in the urine, pain with urination, and low back pain. It is caused when epithelial cells that line the bladder become ma ...

) may appear similar under the

microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...

, but PSAP and PSA staining can help differentiate them; prostate adenocarcinoma often stains with PSA and/or PSAP, while urothelial carcinoma does not.

HIV

PAP may play an important role in the transmission of

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immu ...

. Researchers at the

University of Ulm Ulm University (german: Universität Ulm) is a public university in Ulm, Baden-Württemberg, Germany. The university was founded in 1967 and focuses on natural sciences, medicine, engineering sciences, mathematics, economics and computer sci ...

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

found that PAP forms fibers made of

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of 7–13 nm in diameter, a beta sheet (β-sheet) secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the hu ...

. They called the fibers Semen-derived Enhancer of Virus Infection (SEVI) and showed that they capture HIV virions promoting their attachment to target cells. The association of PAP with HIV may increase the ability of the virus to infect human cells "by several orders of magnitude." PAP may be a future target of efforts to combat the spread of HIV infection.

Pain suppression

A study at the

University of North Carolina The University of North Carolina is the multi-campus public university system for the state of North Carolina. Overseeing the state's 16 public universities and the NC School of Science and Mathematics, it is commonly referred to as the UNC Sys ...

and

University of Helsinki The University of Helsinki ( fi, Helsingin yliopisto, sv, Helsingfors universitet, abbreviated UH) is a public research university located in Helsinki, Finland since 1829, but founded in the city of Turku (in Swedish ''Åbo'') in 1640 as the ...

suggested that PAP could have potent antinociceptive, antihyperalgesic, and antiallodynic effects that last longer than

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies ('' Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. Ther ...

. One dose of PAP lasted for up to three days, much longer than the five hours gained with a single dose of morphine. When in distress, nerve cells release a chemical known as

adenosine triphosphate Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms ...

(ATP) which in turn invokes a painful sensation. ATP is broken down into AMP (

adenosine monophosphate Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine; it is an ester of phosphoric acid and the nucleoside adenosine. As a substitu ...

), which PAP converts into

adenosine Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9-glycosidic bond. Adenosine is one of the four nucleoside buildin ...

, a molecule known to suppress pain.

History

PSAP was the first useful

serum Serum may refer to: *Serum (blood), plasma from which the clotting proteins have been removed **Antiserum, blood serum with specific antibodies for passive immunity * Serous fluid, any clear bodily fluid * Truth serum, a drug that is likely to mak ...

tumour marker and emerged in the 1940s and 1950s.

References

External links

* {{Tumor markers HIV/AIDS Tumor markers Prostate Prostate cancer