ACO1 and cholangiocarcinoma: Both ACO1 and IREB2 genes were lowly expressed in breast-invasive carcinoma (BRCA), rectum adenocarcinoma (READ), cholangiocarcinoma (CHOL), colon adenocarcinoma (COAD), KIRC, pheochromocytoma, and paraganglioma (PCPG), as well as uterine corpus endometrial carcinoma (UCEC) assessed with the matching non-tumorous tissues (Figures 1A, B).