COX4I1 and neoplasm: In Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteomics data,27 we found that mitochondrial markers commonly used in immunohistochemistry, COX4I1 (localized on the mitochondrial inner membrane) and TOMM20 (localized on the mitochondrial outer membrane), were upregulated in CMS2/3, as was the key activator of mitochondrial transcription, mitochondrial transcription factor A (TFAM) (Figure S3D).