Pretreatment of cancer cells with actinomycin D, a transcription inhibitor, almost abolished EGF-enhanced HIF-1α expression in GSCs (Fig. 1H), LN229, and U251 cells (Supplementary Fig. S1H), suggesting that transcriptional regulation of HIF-1α is essentially involved in response to EGFR activation. Here, HIF1A is linked to cancer.