HIF1A and cancer: On the one hand, the introspection into the complex interrelationship between hypoxia-inducible factor 1 (HIF-1) and mitochondria is very important in terms of its influence on mitochondrial structure, metabolism and respiratory function, and on the other hand, the mitochondrial activation of enzymes, the respiratory chain, the complex and decoupling proteins, all of which influence HIF-1 balance and functioning, are essential for designing and applying new high-tech, effective molecular tools and interventions in cancer therapy.