GFAP and Alzheimer disease: In situ hybridization and co-immunofluorescent staining methods to analyze AD, PD, HD, ALS, and MS samples revealed a high degree of co-localization of the astrocyte markers S100β and GFAP and the A1 marker C3 in disease-relevant brain regions, indicating that the astrocytes present had adopted a pro-inflammatory phenotype [76].