S100A4 and amyotrophic lateral sclerosis: Furthermore, in analogy with its functions in inflammation and motility, S100A4 up-regulation in ALS-affected spinal cord could be potentially correlated to these features in the CNS, such as the massive migration of astrocytes and microglia towards the site of injury [53] and to the formation of the glial scar [20] and reactive gliosis, which characterize ALS-affected tissues [54].