Taken together, it may be concluded that the acute ischemic conditions are conducive for markedly elevated production of H2S. We mimicked such conditions by overexpressing CBS in SH-SY5Y neuroblastoma cells and observed a massive increase in H2S production when the overexpressing cells were exposed to high substrate conditions but not substrate concentrations that may reflect normal physiological conditions (Singh et al., 2009; Stipanuk and Ueki, 2011). The gene discussed is CBS; the disease is neuroblastoma.