S100B and Alzheimer disease: S100B in biological fluids is regarded to be a reliable biomarker of active neural injury [4] but, more recently, evidence is accumulating that indicates that this protein plays a key role in the pathogenic processes of neural disorders for which it also acts as a biomarker, including acute brain injury, Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis [5].