title: Retraction Notice to: Betatrophin: A Hormone that Controls Pancreatic β Cell Proliferation.
authors.affiliation: Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Yi
authors.affiliation: Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.
authors.forename: Ji-Sun
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA. Electronic address: dmelton@harvard.edu.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Melton