S100B and central nervous system cancer: The changes in the expression levels of S100B during certain phases of neural cell development in vivo and in vitro [22, 24], the enhanced S100B expression in reactive astrocytes (astrogliosis) [57] and gliomas (as well as in several nonnervous tumor cells) [4–6] and the involvement of intracellular S100B in cell proliferation and differentiation [12, 21–23] call for a detailed analysis of the regulation of S100B expression at the transcriptional and posttranscriptional level and of physiologically relevant interactions of S100B within cells.