Changes in mitochondrial function, such as an increase in mitochondrial population, may affect the metabolic profile of cancer cells and alter the metabolism (105), which in turn, can result in the accumulation of metabolites such as succinate or fumarate (produced by SDH enzyme), which have been shown to stabilize HIF-1α and promote HIF-1 expression (105, 112). The gene discussed is HIF1A; the disease is cancer.