NDRG1 and neoplasm: Numerous genes known to be highly expressed in proliferating cells (Tfrc, metallothioneins genes) were upregulated by the HPD while tumor suppressor genes (Ppp2r2a, Ndrg1 and Prdx1) were downregulated by the HPD (q < 0.01) (Fig. 6a) [29–33].