In a high-risk stage 4 tumor, EPAS1 was typically only expressed in blood vessels expressing high levels of ENG. Also, in a restricted area of the tumor containing strong focal expression of TH EPAS1 expression was primarily restricted to ENG+ cells, indicating that in high-risk tumors EPAS1 is predominantly expressed in stromal endothelial cells. The gene discussed is EPAS1; the disease is neoplasm.