We therefore hypothesize that both intracellular and extracellular redox signaling may be required for the protective/proliferative functions of TRX in metabolically‐intensive cancer cells, whereas slower‐metabolizing cells such as EML and cord blood stem cells require only extracellular TRX functions and non‐redox intracellular mechanisms (as could be exerted by oxidized ORP100S) to survive cellular stress and proliferate. This evidence concerns the gene TXN and cancer.