Evaluating soluble Axl as a biomarker for glioblastoma: A pilot study

Document Type

Article

Publication Date

1-1-2024

Publication Title

PLoS One

Abstract

With current imaging, discriminating tumor progression from treatment effect following immunotherapy or oncolytic virotherapy of glioblastoma (GBM) is challenging. A blood based diagnostic biomarker would therefore be helpful. Axl is a receptor tyrosine kinase that is highly expressed by many cancers including GBM. Axl expression is regulated through enzymatic cleavage of its extracellular domain. The resulting fragment can be detected in serum as soluble Axl (sAxl). sAxl levels can distinguish patients with melanoma, hepatocellular carcinoma, and pancreatic ductal adenocarcinoma from healthy controls. This is a pilot study to determine if sAxl is a candidate biomarker for GBM. The sAxl levels in the serum of 40 healthy volunteers and 20 GBM patients were determined using an enzyme-linked immunosorbent assay (ELISA). Pre- and post- operative sAxl levels were obtained. Volumetric MRI evaluation provided GBM tumor volume metrics. There was no significant difference in the sAxl levels of the volunteers (30.16±1.88 ng/ml) and GBM patients (30.74±1.96 ng/ml) p = 0.27. The postoperative sAxl levels were significantly higher than preoperative levels (32.32±2.26 ng/ml vs 30.74±1.96 ng/ml, p = 0.03). We found no correlation between tumor volume and sAxl levels. Axl expression was low or absent in 6 of 11 (55%) patient derived GBM cell lines. Given the wide range of Axl expression by GBM tumors, sAxl may not be a reliable indicator of GBM. However, given the small sample size in this study, a larger study may be considered.

Medical Subject Headings

Humans; Axl Receptor Tyrosine Kinase; Receptor Protein-Tyrosine Kinases; Glioblastoma; Proto-Oncogene Proteins; Pilot Projects; Biomarkers, Tumor; Male; Female; Middle Aged; Adult; Brain Neoplasms; Aged; Magnetic Resonance Imaging; Case-Control Studies; Enzyme-Linked Immunosorbent Assay

PubMed ID

38968207

Volume

19

Issue

7

First Page

0301739

Last Page

0301739

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