For example, increased free zinc concentration has been proposed to stabilize hypoxia-inducible factor-1 (HIF-1) and thus influence processes such as glycolysis, apoptosis, and angiogenesis.74–77 Moreover, free zinc inhibits thioredoxin reductase,72 a key mediator in the cellular response to oxidative stress that is frequently overexpressed in cancer.78–80. This evidence concerns the gene PRDX5 and cancer.