COX4I2 and cancer: The role of the gene has not been intensively studied in cancer, but it was shown that under hypoxic conditions, CHCHD2 is translocated from the mitochondrial intermembrane space to the nucleus, where it binds an oxygen-responsive element in the promoter of cytochrome oxidase 4I2 (COX4I2), encoding a subunit of complex IV of the electron transport chain, and increases its expression.