CAT and cancer: Plasma induced a high level of H2O2 in cancer cells as compared to normal cells, while in the presence of CAT scavengers; as expectedly, the level of H2O2 decreased from 30% to 60% (p < 0.001) in all cell lines as compared to the plasma-treated group whereas NAP decreased H2O2 levels by 20% to 40% (p < 0.05) in all cell lines after being exposed to plasma alone.