To determine whether peroxynitrite played a relevant role in tumor cell survival in NF2 schwannoma cells, we prevented endogenous production of peroxynitrite by inhibiting NOS activity with L-NAME, scavenging superoxide and peroxynitrite using the iron porphyrin FeTCPP (36), and by incubating the cells with urate to directly scavenge peroxynitrite-derived radicals. This evidence concerns the gene NOS1 and schwannoma.