{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"S100 protein is a type of low-molecular weight protein found in vertebrates, characterized by two calcium-binding sites of the helix-loop-helix conformation. S100 is normally present in cells derived from the neural crest (Schwann cells, melanocytes and glial cells), chondrocytes, adipocytes, myoepithelial cells, macrophages, Langerhans cells, dendritic cells, and keratinocytes. It may be present in some breast epithelial cells. Several members of the S100 protein family are useful as markers for certain tumors and epidermal differentiation. According to literature, S100 can be found in melanomas, 50% of malignant peripheral nerve sheath tumors, and clear cell sarcomas."}]}]}