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Devender Sharma
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EP1.09 - Pathology (ID 199)
- Event: WCLC 2019
- Type: E-Poster Viewing in the Exhibit Hall
- Track: Pathology
- Presentations: 1
- Now Available
- Moderators:
- Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
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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 | Author(s): Devender Sharma
- Abstract
Background
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.
ConclusionIndicator
Value
95% Confidence interval
Sensitivity
94.44%
72.71% to 99.86%
Specificity
63.64%
30.79% to 89.07%
Positive likelihood ratio
2.6
1.18 to 5.72
Negative likelihood ratio
0.09
0.01 to 0.62
Positive predictive value
80.95%
65.86% to 90.35%
Negative predictive value
87.50%
49.74% to 98.02%
Accuracy
82.76%
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.
