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Ruth Roman
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P3.04 - Immunooncology (Not CME Accredited Session) (ID 970)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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P3.04-13 - PD-L1-Gene Expression by nCounter Correlates with PD-L1 Protein Expression in Advanced Non-Small Cell Lung Cancer (NSCLC) (ID 13944)
12:00 - 13:30 | Author(s): Ruth Roman
- Abstract
Background
PD-L1 immunohistochemistry (IHC) staining is a Food and Drug Administration-approved marker to identify patients for immunotherapy treatment in advanced non-small cell lung cancer (NSCLC). However, several antibodies and cut-off criteria have been used and pathological evaluation involves a certain degree of subjectivity. Multiplexed technologies can be of help in this setting and provide an objective measurement of PD-L1 levels.
a9ded1e5ce5d75814730bb4caaf49419 Method
A 7-gene ‘immune signature’ comprising CD4, CD8, PD-1, PD-L1, IFNG, GZMM and FOXP3 was incorporated into our routine clinical practice as part of a customized nCounter panel (NanoString Technologies), which simultaneously screens for gene fusions (ALK, ROS1, RET and NTRK1), MET overexpression and MET exon 14-skipping mutations. Formalin-fixed paraffin embedded (FFPE) samples from advanced NSCLC patients were analyzed with the panel and compared with PD-L1 IHC evaluation on tumor cells, using 22C3 clone antibody.
4c3880bb027f159e801041b1021e88e8 Result
Since 2017, a total of 296 FFPE samples have been analyzed with the nCounter panel. PDL-1 IHC has been performed in 113 FFPE samples, as requested by the oncologist. All samples were evaluable for nCounter and IHC (100%). By IHC, 48/113samples (42.5%) were scored as negative for PD-L1 protein expression, whereas 65/113 (57.5%) were evaluated as positive. Of those, 39 presented moderate (≥1-49%) and 26 (23%) high PD-L1 staining (≥50%). Using an appropriate cut-off value, the levels of PD-L1 mRNA, as determined by the nCounter panel, closely correlated the PD-L1 IHC evaluation, with a 78% of concordance and a 0.554 Cohen’s kappa (confidence interval 95% 0.400- 0.709).
8eea62084ca7e541d918e823422bd82e Conclusion
PD-L1 mRNA expression closely correlates with PD-L1 protein expression. Clinical validation is warranted to determine if nCounter can be an alternative to IHC for PD-L1 evaluation.
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