Although NO has been associated with tumour growth, through increasing vascular permeability, stimulating angiogenesis and invasiveness,19,20 it also induces apoptosis in tumour cells,21,22 particularly at higher levels.23 Chemotherapy resistance in hypoxic tumour cells can be attenuated by low concentrations of NO mimetics such as isosorbide dinitrate in an effect that is at least partly mediated by inhibition of the NFkB anti-apoptotic pathway.24,25. The gene discussed is NFKB1; the disease is neoplasm.