Pre- and postoperative plasma concentrations of five novel candidate biomarker proteins in patients with high- and low-grade gliomas.

Abstract

21 Background: Current imaging techniques are unable to accurately measure tumor burden in gliomas, because they rely on blood-brain barrier (BBB) permeability that is altered following surgery, radiation, steroids, and antiangiogenic therapies. This often leads to misinterpretation of disease status and incorrect clinical decisions. The development of tumor-specific blood-based markers for gliomas is therefore critically important. This study evaluates the detectability of five novel protein biomarker candidates in the plasma of patients with gliomas: neurogranin, ICAM-5, beta-synuclein, brain-derived neurotrophic factor (BDNF), and glial fibrillary acidic protein (GFAP). These biomarker candidates were chosen because of their specificity for brain tissue. Methods: Pre- and postoperative plasma samples were obtained from patients with newly diagnosed gliomas with IRB approval. Plasma concentrations were measured in duplicates using an electrochemiluminescent immunoassay with a lower limit of quantification of >0.04ng/mL (GFAP) and >0.02 ng/mL (other markers). Results: Plasma levels were detectable for all 5 tested markers at baseline and postoperatively. Baseline levels were highly variable and postoperative GFAP levels were much higher than preoperative levels likely related to brain injury (see table). Conclusions: Five potentially useful protein markers have been identified in the plasma of patients with gliomas. Further studies are underway to assess the specificity of each marker and its ability to detect dynamic changes in tumor burden. [Table: see text]