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EP1.09 - Pathology (ID 199)
- Event: WCLC 2019
- Type: E-Poster Viewing in the Exhibit Hall
- Track: Pathology
- Presentations: 2
- Now Available
- Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
EP1.09-05 - Correlation of ROS1 (D4D6) Immunohistochemistry with ROS1 FISH Analysis in Lung Adenocarcinoma: Is IHC a Reliable Screening Tool? (Now Available) (ID 2437)
08:00 - 18:00 | Presenting Author(s): Shivani Sharma
ROS1 gene rearrangement in the lung adenocarcinomas is a one of the targetable non- overalapping genomic alterations (1-3%) besides, EGFR mutation, KRAS mutation, ALK fusion, and many others in patients with non small cell lung carcinomas. Lung adenocarcinoma that exhibit ROS1 gene rearrangement, respond to the targeted inhibitor, crizotinib. Various techniques such as Fluorescent in situ hybridization(FISH), immunohistochemistry(IHC), next generation sequencing and RT Polymerase chain reaction are used to detect ROS1 mutations. We evaluated the correlation between ROS1 IHC and FISH analysis considering FISH as the gold standard method to determine the utility of IHC as a screening method for lung adenocarcinoma.Method
Twenty-nine lung adenocarcinoma patients were retrospectively analyzed for ROS1 rearrangement. Each case underwent IHC and FISH analysis. ROS1 IHC was performed using D4D6 antibody clone on Ventana Benchmark platform. A positive and a negative control were run with each case. The analysis was based on H score system that calculates a score from 0 to 300 according to both the intensity of tumor cells (cytoplasmic) staining and the percentage of cells stained.
FISH analysis was performed on the tumor area marked on Hematoxylin and Eosin stained slides. Dual colour break apart probe was used and the hybridization pattern was considered positive when > 15% of the tumor cells scored showed a gene rearrangement involving the ROS1 gene.Result
Among a total of 29 cases, 17 cases were positive by IHC and FISH analysis (true positive) while seven cases were negative by both the techniques (true negative). Four cases were positive by IHC but were negative on FISH analysis (false positive by IHC) and one case was found to be negative on IHC but positive by FISH analysis (false negative). Subsequently various indicators were calculated as shown in table 1.
95% Confidence interval
72.71% to 99.86%
30.79% to 89.07%
Positive likelihood ratio
1.18 to 5.72
Negative likelihood ratio
0.01 to 0.62
Positive predictive value
65.86% to 90.35%
Negative predictive value
49.74% to 98.02%
1. ROS1 IHC using antibody D4D6 has high sensitivity but the specificity of detection of ROS1 gene rearrangement is low.
2. All cases that are positive by ROS1 IHC, should be confirmed by FISH testing and this stands as a reliable and economic approach to screen ROS1 positive lung adenocarcinomas.
EP1.09-07 - Detection of EGFR Mutation by Automated and Rapid qPCR Based Biocartis Idylla<sup>TM</sup> System in Lung Cancer Patients (Now Available) (ID 2376)
08:00 - 18:00 | Presenting Author(s): Shivani Sharma
Detection of EGFR mutations in subset of Non-small cell lung carcinoma (NSCLC) has significantly changed the therapeutic management strategies in lung cancer. The Biocartis IdyllaTM EGFR detection system is used for the qualitative detection of EGFR mutations (exon 18 (G719A/C/S), exon 20 (T790M, S768I), exon 21 (L858R, L861Q) mutations, exon 19 deletions and exon 20 insertions). The system is unique as it covers the entire process from sample to result with an integrated sample preparation, followed by real time PCR amplification and detection of the targeted sequences. We present the data of series of 38 NSCLCs tested on this system with discussion on the advantages and disadvantages of the assay system.Method
A series of thirty-eight patients of NSCLC from July 2018 to March 2019 were included in the study. An H and E stained slide was prepared from the Formalin fixed paraffin embedded (FFPE) block to document the tumor content in each case. A cut off of 10-15% tumor content was set. About 10 sections were cut with a thickness of 10 micron. Using a new razor blade, the FFPE tissue sections were scrapped onto wet filter papers. Finally, the cartridges are loaded. The IdyllaTM EGFR specific software (EGFR TTP) automatically analyzes the obtained PCR data. The test includes an integrated sample processing controls to verify adequate completion of the sample to the result process. The clinical and demographic data of these cases was analysed.Result
The median age of the population was 66 years. Male to female ratio was 1.5:1. Of total 38 cases, 15 were positive for EGFR mutation (39.4%). 10 cases were positive for Exon 19 deletion (66.6%) and 5 cases were positive for L858R mutation(33.3%).Conclusion
1. The IdyllaTM mutation assay has an edge over conventional EGFR detection system of detecting 51 mutations and indels versus 21 mutations and indel.
2. Turn around time of this assay is average of 4 to 5 hours as compared to 12-48 hours of the conventional assay.
3. The system gains appreciation for minimum requirement of high end expertise required for the testing and interpretation of the results, making it valuable to reach to the masses and provide rapid treatment base for lung cancer patients.
4. The disadvantage of this system is the non-availability of extracted DNA for additional testing.