NR2E3 and cancer: Although numerous FDA-approved RNR inhibitors exist for anti-cancer chemotherapy (e.g., hydroxyurea, gemcitabine, gallium nitrate [57,58,59]), their mechanisms are based on either direct enzyme inhibition (e.g., hydroxyurea and gallium nitrate [60,61]) or on indirect alterations of nucleoside pools (e.g., gemcitabine [62]) and, therefore, they are unlikely to perturb the RNR-A3 interaction.