S100A4, also known as S100 calcium-binding protein A4, belongs to the S100 super-family of proteins containing 2 EF-hand calcium binding domains. This protein is ubiquitously overexpressed and is localized in the cytoplasm and/or nucleus. S100A4 may play a role in motility, invasion, and tubulin polymerization. Chromosomal rearrangements and altered expression of the S100A4 gene have been implicated in tumor metastasis.