Pre- and post-operative plasma glial fibrillary acidic protein levels in patients with newly diagnosed gliomas

Abstract

Therapies that disrupt or repair blood–brain barrier integrity can result in major changes in MRI images even when the tumor volume remains constant. Thus, a reliable blood-based tumor biomarker could significantly improve clinical care and research studies in these patients. This study was performed to assess plasma concentrations of glial fibrillary acidic protein (GFAP) in patients with high- and low-grade gliomas before and after debulking surgery. Pre-operative plasma was collected from 33 patients with radiation- and chemotherapy-naïve gliomas. Additional plasma was collected 24–48 h postoperatively from 23 of these patients. Plasma GFAP (pGFAP) concentrations were determined using an electrochemiluminescent immunoassay and were analyzed as a function of tumor grade, tumor GFAP expression, the integrity of the blood-brain barrier, and post-operative status. Detectable pGFAP levels (≥0.04 ng/mL) were found pre-operatively in 52 % of patients and post-operatively in 96 %. Detectable pGFAP was more common in patients with WHO grade IV (100 %) than WHO grade III (56 %) or WHO grade II gliomas (20 %). No patient with undetectable GFAP had WHO grade IV glioma. Higher pGFAP concentrations were also associated with contrast enhancement but not related to tumor GFAP expression. GFAP is commonly detected in the plasma of patients with high-grade gliomas. pGFAP levels rise rather than fall following debulking surgery which is probably a result of surgical trauma. GFAP remains a potentially informative plasma biomarker for gliomas. Longitudinal studies are required to correlate pGFAP levels with patient outcomes.

Serum levels of GFAP and EGFR in primary and recurrent high-grade gliomas: correlation to tumor volume, molecular markers, and progression-free survival

“…The increase in serum GFAP levels after surgical tumor resection is consistent to a previous study where plasma GFAP values were elevated 24-48 h after surgery in 83 % of patients including both low-grade and high-grade gliomas [9]. Furthermore, post-operative serum GFAP values in our cohort showed no correlation to either enhancing residual tumor volume or to EOR%.…”

“…Accordingly, serum GFAP level above 0.014 ng/ml provided a sensitivity of 86 % and specificity of 85 % for the diagnosis of GBM. Our results correspond to previous studies confirming the diagnostic value of serum GFAP in differentiating GBM from gliomas of lower grade [8,9,22]. High serum GFAP value in one control subject remains unclarified as there was no history of brain trauma, brain MRI was normal, and after 10 months of follow-up this subject remained neurologically symptom-free.…”

“…Serum levels of GFAP are known to be elevated after stroke and traumatic brain injury [6,7]. There is increasing evidence that blood levels of GFAP are also elevated in primary HGGs prior to surgical resection implicating that serum GFAP is a diagnostically relevant biomarker [8][9][10]. However, its prognostic value nor its association to established prognostic markers such as IDH1 mutation, have not been examined.…”

Roles and Potential Clinical Applications of Intermediate Filament Proteins in Brain Tumors

“…65 Interestingly, the serum levels of GFAP and antibodies against GFAP increase with increasing tumor load. [62][63][64][65] Monitoring these levels after surgery and during treatment could be clinically relevant to detect relapse after surgery and to evaluate the efficacy of clinical treatment.…”

Urinary diagnostic proteomic markers for dynapenia in cancer patients

“…This might be a potential misidentification, or might be indicative of kidney dysfunction. GFAP was shown to be a marker for axonal damage in chronic neuropathies (32), and has been reported to be associated with trauma and was found frequently in various gliomas (33). Its modulation is therefore potentially due to cancer and cancer conditions rather than dynapenia.…”