USP22 and glioblastoma: The first report of the cellular localization of Usp22 in the pseudo-palisade tissue and its colocalization with the mitophagy marker Parkin, which is recruited to mitochondria in case of respiratory defects and mitochondrial misfunctioning, is in addition remarkable and once more indicates the relationship between Usp22 and the capability of glioblastoma cells to survive in hypoxic conditions.