In cells of malignant tumors, including GBM, hypoxia caused by a decrease in hemoglobin, on the contrary, leads not to death, but supports rapid proliferation of these cells through various mitochondrial and biochemical mechanisms by: free radicals formation affecting nucleotides formations, increasing HIF-1α (hypoxia-inducible factor-1α), VEGF signaling pathway increase and more (43–45). The gene discussed is HIF1A; the disease is glioblastoma.