The downregulation of MANTIS expression, controlled by histone demethylase JARID1B, was observed in the lungs of patients with idiopathic pulmonary arterial hypertension, and the upregulation was observed in carotid arteries of Macaca fascicularis under an atherosclerosis regression diet, and in endothelial cells isolated from human glioblastoma patients. The gene discussed is SMANTIS; the disease is atherosclerosis.