HSPD1 and neoplasm: Furthermore, in tumor cells, mitochondrial HSP60 acts as a regulator of mitochondrial permeability transition by association with cyclophilin D (CypD, a component of the mitochondrial permeability transition pore), which occurs in a multichaperone complex composed of HSP60, HSP90, and tumor necrosis factor receptor-associated protein-1 (TRAP1).