RT-PCR assay to detect FGFR3::TACC3 fusions in formalin-fixed, paraffin-embedded glioblastoma samples.
Neurooncol Pract
; 11(2): 142-149, 2024 Apr.
Article
in En
| MEDLINE
| ID: mdl-38496910
ABSTRACT
Background:
One targeted treatment option for isocitrate dehydrogenase (IDH)-wild-type glioblastoma focuses on tumors with fibroblast growth factor receptor 3transforming acidic coiled-coil-containing protein 3 (FGFR3TACC3) fusions. FGFR3TACC3 fusion detection can be challenging, as targeted RNA next-generation sequencing (NGS) is not routinely performed, and immunohistochemistry is an imperfect surrogate marker. Fusion status can be determined using reverse transcription polymerase chain reaction (RT-PCR) on fresh frozen (FF) material, but sometimes only formalin-fixed, paraffin-embedded (FFPE) tissue is available.Aim:
To develop an RT-PCR assay to determine FGFR3TACC3 status in FFPE glioblastoma samples.Methods:
Twelve tissue microarrays with 353 historical glioblastoma samples were immunohistochemically stained for FGFR3. Samples with overexpression of FGFR3 (nâ =â 13) were subjected to FGFR3TACC3 RT-PCR on FFPE, using 5 primer sets for the detection of 5 common fusion variants. Fusion-negative samples were additionally analyzed with NGS (nâ =â 6), FGFR3 Fluorescence In Situ Hybridization (nâ =â 6), and RNA sequencing (nâ =â 5).Results:
Using RT-PCR on FFPE material of the 13 samples with FGFR3 overexpression, we detected an FGFR3TACC3 fusion in 7 samples, covering 3 different fusion variants. For 5 of these FF was available, and the presence of the fusion was confirmed through RT-PCR on FF. With RNA sequencing, 1 additional sample was found to harbor an FGFR3TACC3 fusion (variant not covered by current RT-PCR for FFPE). The frequency of FGFR3TACC3 fusion in this cohort was 9/353 (2.5%).Conclusions:
RT-PCR for FGFR3TACC3 fusions can successfully be performed on FFPE material, with a specificity of 100% and (due to limited primer sets) a sensitivity of 83.3%. This assay allows for the identification of potential targeted treatment options when only formalin-fixed tissue is available.
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Neurooncol Pract
Year:
2024
Document type:
Article
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