Higher expression of latent transforming growth factor beta binding protein 2 (LTBP2) and periostin (POSTN) was found in all PAH patients (Fig. 7A, B), whereas lower expression of secreted phosphoprotein 1 (SPP1) and limbic system associated membrane protein (LSAMP) was found in most of the PAH patients except the HPAH patients (Fig. 7C, D). Here, LSAMP is linked to heritable pulmonary arterial hypertension.