title: Erratum to: PD-1, PD-L1, PD-L2 expression in the chordoma microenvironment.
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Mathios
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Ruzevick
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Jackson
authors.affiliation: Department of Dermatology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Haiying
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Sagar R
authors.initials: SR
authors.lastname: Shah
authors.affiliation: Department of Dermatology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Janis M
authors.initials: JM
authors.lastname: Taube
authors.affiliation: Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burger
authors.affiliation: Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Edward F
authors.initials: EF
authors.lastname: McCarthy
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Quinones-Hinojosa
authors.affiliation: Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Drew M
authors.initials: DM
authors.lastname: Pardoll
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. mlim3@jhmi.edu.|Department of Neurosurgery, Johns Hopkins Hospital, 600 N. Wolfe Street, Neurosurgery - Phipps 123, Baltimore, MD, 21287, USA. mlim3@jhmi.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Lim