TRAP1 and cancer: The factors responsible for the accumulation of succinate in cancer cells are summarized as follows [108]: (i) mutations in SDH; (ii) TRAP1—a key protein responsible for inhibiting SDH; TRAP1 is a mitochondrial chaperone, which is highly expressed in many types of cancer cells; TRAP1 inhibits respiratory complex II to decrease SDH activity, thus leading to high concentrations of succinate; (iii) the glyoxylate shunt, converting isocitrate to succinate by the enzyme isocitrate lyase; and (iv) the degradation of glutamate.