Compared with the normal controls, the expression of C-X-C motif chemokine ligand 8 (CXCL8) in idiopathic pulmonary arterial hypertension (IPAH) is increased and was associated with an increased risk of IPAH and unfavorable clinical features (34). The gene discussed is CXCL8; the disease is idiopathic pulmonary arterial hypertension.