NDRG1 and neoplasm: Contrary to these findings, Said et al. observed higher NDRG1 mRNA and protein expression levels in grade IV glioma (n = 15) compared with grade II glioma (n = 15) and suggested that this is caused by the hypoxic state of the tumor, as NDRG1 is a downstream target of hypoxia-inducible factor 1 (HIF-1).