We have also shown that, in human malignant fibrous histiocytoma (MFH) xenografts, transcutaneous CO2 decreases expression of HIF-1α and induces mitochondrial apoptosis, in turn increasing PGC-1α and mitochondrial transcription factor A (TFAM) [9], [14]. The gene discussed is PPARGC1A; the disease is undifferentiated pleomorphic sarcoma.