NOS2 and chronic obstructive pulmonary disease: Additionally, we quantified DNA methylation in the inducible nitric oxide synthase gene (iNOS, also known as NOS2, Genbank accession number AF017634) which is involved in the production of nitric oxide and plays an important role in a variety of cardio-pulmonary processes including asthma [12], chronic obstructive pulmonary disease [37], and cardiovascular health [38].