Related Experiment Video
Updated: Nov 8, 2025
Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
Published on: June 8, 2019
FGFR3 overexpression is a useful detection tool for FGFR3 fusions and sequence variations in glioma
Jens Schittenhelm1,2, Lukas Ziegler2, Jan Sperveslage3,4
1Center for Neuro-Oncology, Comprehensive Cancer Center Tuebingen-Stuttgart, University Hospital of Tuebingen, Eberhard Karls University of Tuebingen, Tuebingen, Germany.
Background:
Fibroblast growth factor receptor (FGFR) inhibitors are currently used in clinical development. A subset of glioblastomas carries gene fusion of FGFR3 and transforming acidic coiled-coil protein 3. The prevalence of other FGFR3 alterations in glioma is currently unclear.
Methods:
We performed RT-PCR in 101 glioblastoma samples to detect FGFR3-TACC3 fusions ("RT-PCR cohort") and correlated results with FGFR3 immunohistochemistry (IHC). Further, we applied FGFR3 IHC in 552 tissue microarray glioma samples ("TMA cohort") and validated these results in two external cohorts with 319 patients. Gene panel sequencing was carried out in 88 samples ("NGS cohort") to identify other possible FGFR3 alterations. Molecular modeling was performed on newly detected mutations.
Results:
In the "RT-PCR cohort," we identified FGFR3-TACC3 fusions in 2/101 glioblastomas. Positive IHC staining was observed in 73/1024 tumor samples of which 10 were strongly positive. In the "NGS cohort," we identified FGFR3 fusions in 9/88 cases, FGFR3 amplification in 2/88 cases, and FGFR3 gene mutations in 7/88 cases in targeted sequencing. All FGFR3 fusions and amplifications and a novel FGFR3 K649R missense mutation were associated with FGFR3 overexpression (sensitivity and specificity of 93% and 95%, respectively, at cutoff IHC score > 7). Modeling of these data indicated that Tyr647, a residue phosphorylated as a part of FGFR3 activation, is affected by the K649R mutation.
Conclusions:
FGFR3 IHC is a useful screening tool for the detection of FGFR3 alterations and could be included in the workflow for isocitrate dehydrogenase (IDH) wild-type glioma diagnostics. Samples with positive FGFR3 staining could then be selected for NGS-based diagnostic tools.
Insights
Fibroblast growth factor receptor 3 (FGFR3) alterations, including fusions, amplifications, and mutations, are present in gliomas. Immunohistochemistry (IHC) is a valuable screening tool for detecting these FGFR3 alterations in glioma patients.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Fibroblast growth factor receptor (FGFR) inhibitors are in clinical development.
- Glioblastomas can harbor FGFR3-TACC3 gene fusions.
- The prevalence of other FGFR3 alterations in glioma remains largely unknown.
Purpose of the Study:
- To investigate the prevalence and spectrum of FGFR3 alterations in glioma.
- To evaluate the utility of FGFR3 immunohistochemistry (IHC) as a screening tool for these alterations.
Main Methods:
- RT-PCR was used to detect FGFR3-TACC3 fusions in 101 glioblastomas.
- FGFR3 IHC was performed on 552 glioma samples and validated in external cohorts.
- Next-generation sequencing (NGS) identified other FGFR3 alterations in 88 samples.
- Molecular modeling was used to analyze novel mutations.
Main Results:
- FGFR3-TACC3 fusions were found in 2% of glioblastomas.
- FGFR3 alterations (fusions, amplification, mutations) were identified in 20% of samples analyzed by NGS.
- FGFR3 IHC demonstrated high sensitivity (93%) and specificity (95%) for detecting FGFR3 alterations, correlating with overexpression.
- A novel FGFR3 K649R mutation affecting Tyr647 phosphorylation was identified.
Conclusions:
- FGFR3 IHC is an effective screening method for identifying FGFR3 alterations in glioma.
- This approach can aid in selecting patients for further molecular testing, such as NGS.
- FGFR3 IHC could be integrated into the diagnostic workflow for isocitrate dehydrogenase (IDH) wild-type glioma.
