NOS2 and pulmonary arterial hypertension: iNOS has been implicated in infectious and inflammatory diseases, neurodegenerative disorders, cancer, and pulmonary emphysema [10–12], and pharmacological blockade of iNOS has been shown to inhibit tumor growth [13], enhance the efficacy of antitumor immunotherapies [14], and ameliorate elastase-induced pulmonary emphysema and pulmonary hypertension [15].