SP1 and glioma: To elucidate the transcriptional regulation of VEGF by TGF-β, 2 major transcription factors known to have multiple response elements on the promoter region of VEGF, namely, specificity protein (SP1) and early growth response (EGR)1 were screened for basal mRNA expression in hCMEC, HUVEC and two glioma cell lines, U87MG and LN-18 (Supplementary Figure 4A–4B).