In Su/Hx-induced PAH models and human PASMCs exposed to hypoxia, DNA topoisomerase IIα expression is markedly upregulated, promoting abnormal cell proliferation and migration through activation of the PI3K/Akt/mTOR pathway, and driving inflammatory cytokine release along with the production of ROS (108). The gene discussed is MTOR; the disease is pulmonary arterial hypertension.