GFAP and neoplasm: In agreement with the staining pattern observed, the U87 cells used in establishing the intracranial tumor were also largely negative for GFAP; however, Nestin that was absent in the cell line was drastically enhanced in the tumor and the level of β3 Tubulin that was abundant in the cell line got reduced in the tumor, suggestive of influence of the microenvironment on expression of these markers (Supplementary Figure 1).