However, overall, it is apparent that hypoxic gliomaspheres mimic the in-vivo tumor condition better than the other tissue culture model as the upregulation of Notch genes (Notch1, Notch2, Notch3, Dll1, Hes1, Hey1 and Hey2) is further enhanced upon exposure to hypoxia. This evidence concerns the gene HEY1 and neoplasm.