SOD3 and neoplasm: Dihydroethidium oxidation, used to measure ·O2− levels, was lower in 1G11-SOD3- than in 1G11-mock-transduced cells, both in basal culture and after incubation with tumor cell-conditioned medium, a stress condition that boosted ·O2− production in mock-transfected cells (Supplementary Fig. 5c).