To investigate the role of nitrated Hsp90 in schwannoma cell proliferation, we doubled the endogenous levels of nitrated Hsp90 by intracellular delivery of peroxynitrite-treated recombinant Hsp90 (fully nitrated protein, NO2Hsp90) in schwannoma cells (Fig. 1A). The gene discussed is HSP90AB1; the disease is schwannoma.