We have proved previously that IL-17 deficiency prevented development of hypoxia-induced pulmonary hypertension and right ventricular hypertrophy [13], results in the present study showed that the expression of p-STAT-3 in RV tissues from the IL-17-deficiency mice was lower than that in the wild-type mice (Fig. 3D), indicating that IL-17 may induce right ventricular hypertrophy through STAT-3 activation. The gene discussed is IL17A; the disease is pulmonary arterial hypertension.