An abnormally glycosylated isoform of erythropoietin in hemangioblastoma is associated with polycythemia

Clin Chim Acta. 2015 Jan 1;438:304-6. doi: 10.1016/j.cca.2014.09.013. Epub 2014 Sep 19.

Abstract

Background: Hemangioblastomas express erythropoietin and the patients often present with polycythemia.

Methods: Serum erythropoietin was measured using a commercial immunoassay, a functional erythropoietin assay and iso-electric focusing.

Results: Despite the polycythemia, serum erythropoietin remained low, while a functional erythropoietin-assay showed a 4-5 higher activity in serum compared to the immunoassay. Iso-electric focusing of serum erythropoietin indicated overrepresentation of highly sialylated erythropoietin isoforms produced by the tumor. As a result, altered affinity of the monoclonal antibody used in the immunoassay for the hypersialylated isoforms was suggested.

Conclusion: Analysis of erythropoietin isoforms may be helpful in distinguishing the ectopic erythropoietin isoforms from normally glycosylated erythropoietin.

Keywords: Erythropoietin isoforms; Glycosylation; Hemangioblastoma; von Hippel–Lindau.

Publication types

  • Case Reports

MeSH terms

  • Antibodies, Monoclonal / chemistry
  • Antibodies, Monoclonal / immunology
  • Artifacts*
  • Central Nervous System Neoplasms / blood*
  • Central Nervous System Neoplasms / complications
  • Central Nervous System Neoplasms / diagnosis
  • Central Nervous System Neoplasms / surgery
  • Erythropoietin / analysis
  • Erythropoietin / metabolism*
  • Glycosylation
  • Hemangioblastoma / blood*
  • Hemangioblastoma / complications
  • Hemangioblastoma / diagnosis
  • Hemangioblastoma / surgery
  • Humans
  • Immunoassay
  • Isoelectric Focusing
  • Male
  • Middle Aged
  • Polycythemia / blood*
  • Polycythemia / complications
  • Polycythemia / diagnosis
  • Polycythemia / surgery
  • Protein Isoforms / analysis
  • Protein Isoforms / metabolism

Substances

  • Antibodies, Monoclonal
  • Protein Isoforms
  • Erythropoietin