Virtual Library
Start Your Search
C. Phanthunane
Author of
-
+
P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
-
+
P2.04-034 - The Study of EGFR Mutation Specific-Antibody for Detection of EGFR Status in Non-Small Cell Lung Cancer (ID 750)
09:30 - 09:30 | Author(s): C. Phanthunane
- Abstract
Background:
Specific somatic mutations of the epidermal growth factor receptor (EGFR) associate with increasing response to EGFR tyrosine kinase inhibitors (TKIs) treatment in NSCLC. Assessment of EGFR mutation status by gene-based assay remains expensive and is not routinely reimbursed in Thailand. The objective of this study is to test a simple immunohistochemical (IHC) method using EGFR mutation-specific antibodies for detection of EGFR status.
Methods:
Specimen from 76 NSCLC patients whose EGFR mutation status had been detected by DNA direct sequencing were collected from January 2010 to July 2014 as the reference standard. We performed IHC analyses using 2 EGFR mutation-specific antibodies to E746-A750 del in exon 19 and the other to L858R in axon 21 for all samples. IHC staining were score as 0 (no, or faint staining intensity in <10% tumor cells), 1+ (faint, staining >10%), 2+ (moderate) and 3+ (strong).
Results:
The reference DNA sequencing showed exon 21 L858R EGFR mutations in 17 (22.4%) patients, exon 19 deletions in 12 (15.8%) patients, G719X mutation in 1 (1.3%) patients, exon 20 insertion in 1 (1.3%) patients, multiple sites mutation in 1 (1.3%) patients and no mutation detected in 46 (52.9%) patients. With the DNA sequencing results were set as the reference standard, the prevalence of mutation detected by IHC-based analyses was 25.8% (8/31), 44.4% (8/18), 100% (7/7) and 66.7% (8/12) respectively, for samples with scores 0, 1+, 2+ and 3+. At IHC cut point value 2+, sensitivity and specificity for antibodies L858R were 52.9% wand 98.3 respectively. Likewise for antibodies E746-A750, cut point value 2+ showed sensitivity and specificity as 50.0% and 95.3% E746-A750 respectively. Additional, indicate similar cut point as score 2 ,PPV and NPV were 66.7% and 91.0% for antibodies E746-A750 and 90.0% and 88% for L858R antibodies.
Conclusion:
A simple IHC-based analysis using EGFR mutation-specific antibodies in this study have good correlation with gene-based for EGFR mutation analysis. In Thailand, these simple IHC cost less for five times, have shorter turn around time than gene-based for EGFR mutation analysis and could be useful where molecular-based assay is not readily accessible.
