HIF1A and neoplasm: Hence, Thomas D et al [46] showed that low NO doses of 10-300 nM induced ERK phosphorylation and HIF-1α (hypoxia induced factor 1α) accumulation in MCF-7 cells, resulting in tumor proliferation and differentiation, while with high doses of NO (> 300 nM), p53 phosphorylation occurs, which is associated with apoptosis induction [46].