S100B and Alzheimer disease: The development of effective pharmacological strategies for modulating S100B function in patients will also require quantifying the contribution of extracellular versus intracellular forms, identifying the S100B-regulated target proteins/cellular processes, and ascertaining the contribution of the five other S100 family members implicated in AD, S100A1, S100A6, S100A7, S100A9, and S100A12 [1,68-70].