Chordomas harbor regions of intratumoral hypoxia that can contribute to treatment resistance.[21, 22] To identify potential therapeutics effective in low oxygen setting, we characterized in vitro propagation of chordoma cells at 2% oxygen and observed increased proliferative rate (Fig 4) and level of vascular endothelial growth factor (VEGF), a transcriptional target of HIF-1α (Fig 4). This evidence concerns the gene HIF1A and chordoma.