EPAS1 and neoplasm: Despite several hundred bulk RNA-sequenced/arrayed neuroblastoma tumors exhibiting a highly significant correlation between high levels of EPAS1 expression and low-risk tumors with favorable outcome (7), some studies have continued to argue that HIF2α acts to fuel tumor growth, partly by imposing an immature state with stem cell–like features that blocks differentiation (5, 11, , , –15).