ATP-binding cassette (ABC) transporters are an evolutionarily conserved family of widely-expressed proteins that use ATP hydrolysis to catalyze the transport of various molecules across extracellular and intracellular membranes. As the largest family of transmembrane proteins, ABC genes comprise several subfamilies. Eukaryotic ABC transporters are largely responsible for trafficking hydrophobic compounds either within the cell, as part of a metabolic process, or outside the cell, for transport to other organs or for secretion from the body. ABCF2 in particular plays a putative role in tumor suppression at metastatic sites and in the endocrine pathway for breast cancer and may be a prognostic marker for clear cell ovarian adenocarcinoma.