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Published on: May 2, 2022
EGFR and gastrointestinal stromal tumor: an immunohistochemical and FISH study of 82 cases
Lisandro F Lopes1, Carlos E Bacchi
1Consultoria em Patologia, Botucatu, Sao Paulo, Brazil.
Abstract:
Gastrointestinal stromal tumor is the most common mesenchymal neoplasm of the gastrointestinal tract. Mutually exclusive KIT or platelet-derived growth factor receptor-alpha mutations are key events in gastrointestinal stromal tumor pathogenesis, and specific treatment targeting KIT/platelet-derived growth factor receptor-alpha activation is available. Epidermal growth factor receptor plays an important role in cancer biology and also constitutes a promising molecular target of therapy. Very few reports have been published in the literature about the relationship between gastrointestinal stromal tumor and epidermal growth factor receptor. The aim of this study was to investigate epidermal growth factor receptor immunohistochemical expression and epidermal growth factor receptor gene amplification in 82 consecutive gastrointestinal stromal tumor cases using tissue microarray technique. Hematoxylin- and eosin-stained sections and clinical information were reviewed, and expression of CD117 (KIT), CD34 and epidermal growth factor receptor was investigated by immunohistochemistry. Epidermal growth factor receptor gene copy number was determined using fluorescence in situ hybridization. Immunohistochemistry revealed that CD117 and CD34 were expressed in 96 and 57% of tumors, respectively. Variable epidermal growth factor receptor protein immunohistochemical overexpression was detected in 96% of gastrointestinal stromal tumor cases, but none of the 75 cases with represented tumor tissue cores and countable fluorescence signals exhibited epidermal growth factor receptor gene amplification by fluorescence in situ hybridization. These results show that there is no correlation between epidermal growth factor receptor protein overexpression by immunohistochemistry and epidermal growth factor receptor gene amplification by fluorescence in situ hybridization. Considering that the mechanisms of epidermal growth factor receptor protein overexpression are not well understood and the possibility that anti-epidermal growth factor receptor therapy may be beneficial for patients with gastrointestinal stromal tumor that overexpresses epidermal growth factor receptor, additional studies are encouraged.
Insights
Gastrointestinal stromal tumors (GIST) frequently overexpress epidermal growth factor receptor (EGFR) protein, but this is not linked to gene amplification. Further research is needed to understand EGFR overexpression in GIST and its therapeutic potential.
Area of Science:
- Oncology
- Gastroenterology
- Molecular Biology
Background:
- Gastrointestinal stromal tumor (GIST) is the most common gastrointestinal mesenchymal neoplasm.
- KIT or platelet-derived growth factor receptor-alpha (PDGFRA) mutations drive GIST pathogenesis, with targeted therapies available.
- Epidermal growth factor receptor (EGFR) is a significant cancer biomarker and therapeutic target, yet its role in GIST is under-explored.
Purpose of the Study:
- To investigate EGFR protein expression via immunohistochemistry and EGFR gene amplification using fluorescence in situ hybridization (FISH) in 82 GIST cases.
- To explore the relationship between EGFR expression, gene amplification, and GIST characteristics.
Main Methods:
- Tissue microarray technique was employed for immunohistochemical analysis of CD117 (KIT), CD34, and EGFR.
- EGFR gene copy number was assessed using FISH on 75 GIST cases with sufficient tumor tissue.
- Clinical information and H&E-stained sections were reviewed.
Main Results:
- CD117 and CD34 expression was observed in 96% and 57% of GIST cases, respectively.
- EGFR protein overexpression was detected in 96% of GIST cases via immunohistochemistry.
- No EGFR gene amplification was found in any of the analyzed GIST cases by FISH, indicating no correlation between protein overexpression and gene amplification.
Conclusions:
- EGFR protein overexpression is common in GIST but is not driven by gene amplification.
- The mechanisms underlying EGFR overexpression in GIST remain unclear.
- Further investigation into EGFR's role and potential anti-EGFR therapy for GIST patients with EGFR overexpression is warranted.
