ENO1 was ubiquitously expressed in the lung sections of PAH patients, including the media, intima, and the perivascular region, suggesting the expression of ENO1 in PASMC, endothelial cells, and monocyte/macrophages, however, it was mainly elevated in the media of the APAH patients (Fig. 1d). This evidence concerns the gene ENO1 and pulmonary arterial hypertension.