CYB5A and glioblastoma: Among the candidate genes found in this study, for example, the cytochrome b5 type A (CYB5A) encodes membrane-bound cytochrome and was found to be one hypoxia-sensitive protein in rat erythrocytes (37); the UDP-glucose 6-dehydrogenase (UGDH) gene was involved in the metabolic adaptation to hypoxic stress in human glioblastoma cells (38).