PRDX5 and pancreatic neoplasm: To determine if Au inhibits thioredoxin reductase activity in pancreatic cancer cells, MIA PaCa-2 pancreatic cancer cells were treated with Au for 3 h and thioredoxin reductase activity was measured by spectrophotometrically following the reduction of 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB) utilizing a thioredoxin reductase assay kit.