S-100 protein

The proteins of the multigene family S -100 calcium -binding proteins of low molecular mass ( 9-13 kDa) and a variety of cellular functions (eg phosphorylation ).

• The S-100 proteins include 19 members, which are expressed in a variety of cell types: Thus, S100B is expressed mainly in glial cells but also in adipocytes, melanocytes and chondrocytes.
• S100A1 found in cardiomyocytes, salivary gland, kidney, muscle and nerve cells of the hippocampus and
• S100A6 in connective tissue and muscle tissue.
• Calprotectin ( S100A8/S100A9-Heterotetramer ) as proof of leukocytes into inflamed tissue, especially suitable for leuco - proof in the intestine in ulcerative, Crohn's disease and other inflammatory by stool sample. Serum value as an alternative marker of inflammation.
• S100A9 as a screening parameter for prostate cancer.

• 2.1 Notes and references

Use in the diagnosis

Since the respective sub-types of proteins found only in certain cell types, they are suitable for medical diagnostics. By concentration changes conclusions regarding conditions in the respective cells and tissues may be drawn.

Histopathology

In the histopathological diagnosis S-100 antibodies are used to immunohistochemically distinguish certain tumor cells, which typically are S-100 positive (eg chondroid tumors, gliomas, nerve sheath tumors, melanomas ) of S-100 - negative tumors.

Neurology

In neurological diagnostic determination of the S-100 protein concentration is used as a marker of cerebral injury. Here it is assumed that it ( eg after a stroke or traumatic brain injury ) comes after a brain injury to a release of S -100B proteins from glial cells in the cerebrospinal fluid into the blood, which can be used diagnostically. Several studies have shown a relatively high negative predictive value, with a slight traumatic brain injury (TBI ) can be ruled out within a few hours after the accident with a simple blood test. On the other hand, S100 increases in serum not very specific: they were also observed in marathon and long distance runners and do not reflect a real damage to the brain resists, but due to the release from skeletal muscle.