In addition, Cyst(e)inase in combination with Auranofin [a thioredoxin reductase (TXNR) inhibitor] or Olaparib [a poly (ADP-ribose) polymerase (PARP) inhibitor] provided synergistic increases in DNA damage, inhibition of cancer cell survival and inhibition of tumor growth in vivo. Here, TXNRD1 is linked to cancer.