GFAP and glioma: The 5’ deletion of the original 2.2-kb GFAP promoter to 1.7 kb did not substantially compromise the promoter strength in U251 cells, a human glioma cell line that strongly expresses GFAP, whereas further deletion to approximately 1.5 kb, which removed the B and C1 regions, resulted in a drastic reduction in the promoter strength to 10% of the original 2.2-kb promoter [16].