HIF1A and neoplasm: Pitfalls therein were and still are complex situation-specific outcomes, such as dependence on cell types, in particular tumor cell types and tumor microenvironment,16 significance of the temporal application (examples are the ischemia reperfusion injury17 or the distinct, often opposing roles of HIF-1α during tumor initiation and during metastatic spread) , as well as the severe side effects in case of rather non-specific pharmacological inhibition.18