For instance, the antioxidant protein thioredoxin 1 (TRX1) is enzymatically active if harboring two -SH groups at cysteine (Cys)32 and Cys35, but becomes inactivated if -SH groups at these two positions were oxidized to disulfides 4, and increased TRX1 protein oxidation was observed in more invasive human prostate cancer cells 5. This evidence concerns the gene TXN and prostate cancer.