Detection of epidermal growth factor receptor mutation in non-small-cell lung carcinoma using cytological and
Haimiao Xu1, Wenyong Sun, Gu Zhang
1Department of Pathology, Zhejiang Cancer Hospital, Hangzhou 310022, China.
Purpose:
Epidermal growth factor receptor (EGFR) mutations are prerequisites for the targeted therapy with anti-EGFR tyrosine kinase inhibitors (TKIs) in non-small-cell lung carcinomas (NSCLCs). In patients with advanced-stage NSCLC, sometimes cytological specimens, including those from fine-needle aspiration cytology (FNAC) and pleural effusion, are the only materials for mutation analysis. The purpose of this study was to compare the results of EGFR mutation detection from cytological specimens and histological samples and to evaluate the difference between them, therefore to assess if cell block is a valid source for detection of EGFR mutation.
Methods:
Forty-seven samples from advanced-stage NSCLCs were obtained with individually matched cell blocks (CBs) from FNAC (29 cases) or pleural fluid (18 cases), and formalin-fixed paraffin-embedded (FFPE) blocks from biopsy (34 cases) or surgical excision (13 cases). CBs and FFPE blocks were simultaneously tested for EGFR hot mutations in exons 18, 19, 20 and 21 by polymerase chain reaction (PCR)-direct sequencing and amplification refractory mutation system (ARMS)-PCR.
Results:
EGFR mutations were identified in 18/47 (38.3%) or 21/47 (44.7%) cases using CBs and 16/47 (34.0%) or 19/47 (40.4%) using FPPE blocks by PCR-direct sequencing or ARMS-PCR, respectively. The incidence of EGFR mutation was not statistically significant between CBs and FFPE blocks using PCR-direct sequencing or ARMS-PCR (p=0.668 or p=0.677, respectively).
Conclusion:
Our study suggests that cytological specimens are optimal for advanced NSCLC. The successful use of these non-invasive specimens in molecular pathology is beneficial for patients requiring targeted therapy.
Insights
Cell blocks from cytological specimens are effective for detecting epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer (NSCLC). This validates the use of non-invasive samples for targeted therapy in advanced NSCLC patients.
Area of Science:
- Oncology
- Molecular Pathology
- Genetics
Background:
- Epidermal growth factor receptor (EGFR) mutations are crucial for targeted therapy in non-small-cell lung carcinomas (NSCLCs) using tyrosine kinase inhibitors (TKIs).
- Cytological specimens like fine-needle aspiration cytology (FNAC) and pleural effusion are sometimes the only available material for mutation analysis in advanced NSCLC.
- Histological samples are traditionally used for molecular testing, but their invasiveness can be a limitation.
Purpose of the Study:
- To compare EGFR mutation detection rates between cytological specimens (cell blocks) and histological samples (FFPE blocks) in advanced NSCLC.
- To evaluate the efficacy of cell blocks as a source for EGFR mutation analysis.
- To determine if cytological specimens are a valid alternative to histological samples for guiding targeted therapy.
Main Methods:
- Forty-seven advanced NSCLC samples were analyzed, including cell blocks (CBs) from FNAC or pleural fluid and formalin-fixed paraffin-embedded (FFPE) blocks from biopsies or surgical excisions.
- EGFR mutations in hot spots (exons 18, 19, 20, 21) were detected using both polymerase chain reaction (PCR)-direct sequencing and amplification refractory mutation system (ARMS)-PCR.
- Simultaneous testing was performed on matched CBs and FFPE blocks to ensure comparability.
Main Results:
- EGFR mutations were detected in 38.3% (PCR-direct sequencing) to 44.7% (ARMS-PCR) of cases using CBs.
- EGFR mutations were detected in 34.0% (PCR-direct sequencing) to 40.4% (ARMS-PCR) of cases using FFPE blocks.
- No statistically significant difference in EGFR mutation detection rates was observed between CBs and FFPE blocks (p=0.668 for PCR-direct sequencing, p=0.677 for ARMS-PCR).
Conclusions:
- Cytological specimens, specifically cell blocks, are optimal for detecting EGFR mutations in advanced NSCLC.
- The use of non-invasive cytological specimens is beneficial for patients requiring EGFR-targeted therapy.
- Cell blocks provide a reliable and effective alternative to histological samples for molecular pathology in NSCLC.
