UCP2 (uncoupling protein 2), an inner mitochondrial membrane protein, can promote autophagy and endocrine resistance in breast cancer via the ROS1 (ROS proto-oncogene 1, receptor tyrosine kinase)–AKT1 (AKT serine/threonine kinase 1)–MTOR signaling pathway [48]. Here, UCP2 is linked to breast cancer.