Reacts with the 21 - 24 kD (the A and B subunits) of the S-100 protein. S-100A is composed of one alpha- and one beta-chain, whereas S-100B is composed of two beta-chains. S-100 is a brain protein normally present in astrocytes, melanocytes, ependymal cells, glial cells and Schwann cells. Langerhans cells in the skin and interdigitating reticulum cells in the paracortex of lymph nodes also stain positively. S-100 occurs in tumors of the central nervous system, such as Schwannomas, ependymomas, astrogliomas, gliastomas and almost all melanomas.
Positive control: human skin.