GFAP and cancer: Similar effects of ACSVL3 knockdown on stem cell marker expression were observed in several low passage primary GBM neurosphere cells directly derived from patient samples (Figure 3B, P < 0.05).Since ACSVL3 expression is reduced following the forced differentiation of GBM neurospheres, we asked if ACSVL3 knockdown is sufficient to promote differentiation of cancer stem cells by examining the expression of the astroglial and neuronal lineage-specific markers GFAP and β-tubulin III (Tuj1).