EPAS1 and breast cancer: A recent study revealed that fibulin-3 plays a role in breast cancer, and showed that downregulation of fibulin-3 in human TNBC Hs578T cells decreased primary tumor growth in an orthotopic xenograft model, by impairing the tumor initiation potential of breast cancer stem cells, downstream of hypoxia inducible factor (HIF2α) [17].