These levels are slightly below the range of 60–140 μg Se/L in serum/plasma generally recognized in the literature published during the last two decades as an adequate or “optimal” Se status for beneficial health effects, including optimization of iodothyronine deiodinases, glutathione peroxidase and selenoprotein P, protection from certain types of cancers, and reduction in total mortality [117]. The gene discussed is SELENOP; the disease is cancer.