S100 calcium binding protein B or S100B is a protein of the S-100 protein family. S100 proteins are localized in the cytoplasm and nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. S100 genes include at least 13 members which are located as a cluster on chromosome 1q21, however, this gene is located at 21q22.3. Alternative Names: SB-100 protein, SB 100, SB 100 protein, S-100 BB Protein, S-100 Protein, S100B, SB-100