RRAS and pulmonary arterial hypertension: In addition, abnormality of endothelin-1 signaling related gene expression including transcription factor AP-1 (JUN), Ras family small GTP binding protein H-Ras (HRAS), RRAS, RRAS2, protein disulfide isomerase family A member 3 (PDIA3), and Src homology 2 domain containing E (SHE) was also found in PAH PAEC (Supplementary Tables S1 and S2) (Fig. 8).