GFAP and glioblastoma: In this study, we first demonstrated that when human GBM cell lines were cocultured with clinically isolated glioblastoma-associated macrophages, this significantly enhanced colony formation ability and tumor sphere generation in association with an increased expression of Sox2, STAT3, interleukin 6 (IL-6), and Nestin and a decrease in glial fibrillary acidic protein (GFAP).