S100A4 is a member of the S100 family of proteins. S100 proteins are localized in the cytoplasm and/or 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. S100A4 may function in motility, invasion, and tubulin polymerization. Chromosomal rearrangements and altered expression of this gene have been implicated in tumor metastasis. S100A4 is highly associated with components of the cytoskeleton and when this gene is upregulated, it changes the cellÍs morphology, making it more susceptible to invasion from proteins, such as cathepsin B and cyclin B1, that contribute to metastasis.[