Pulmonary vessels and circulating progenitor cells isolated from patients showed down regulation of microRNA-124 (miR-124), resulting in abnormal metabolism and proliferation of PAH epithelial cells through PTPB1 and PKM1/PKM2, which affects the normal metabolism of pulmonary epithelial cells and promotes the formation of pulmonary hypertension (33). This evidence concerns the gene PKM and pulmonary hypertension.