Various chaperones, including COX15, COX17, COX20, HIGD2A, and SCO1/2, have been implicated in diverse aspects of Complex IV assembly.[21, 27] While depletion of these chaperones can damage the Complex IV production, none of them showed an elevated expression in the blood cancer patient samples (Figure S4, Supporting Information; GENT2 database). This evidence concerns the gene COX20 and cancer.