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Lin Li
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P2.09 - Pathology (Not CME Accredited Session) (ID 958)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.09-04 - PD-L1 Expression in Primary Lung Adenocarcinoma and its Relation with EGFR / KRAS Mutation and Clinicopathological Features (ID 12831)
16:45 - 18:00 | Presenting Author(s): Lin Li
- Abstract
Background
Programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway-targeted immunotherapy is becoming standard practice in the management of lung cancer. Theexpression of PD-L1protein is expected to apply to evaluatethe prognosis or to predict the response to PD-1-blocking antibodies. The immunohistochemistry(IHC) assay forPD-L1, 22C3 pharmDx, has revealed that about30% of all non-small cell lung cancer (NSCLCs) express the PD-L1 with a high level. The association between PD-L1 positivity and the clinicopathological features in lung adenocarcinoma (ADC) remains unclear, however.
a9ded1e5ce5d75814730bb4caaf49419 Method
We retrospectively evaluated the PD-L1 expression in the surgically resected tumor tissues by IHC with the 22C3 assay, from 233 primary lung ADC patients. The PD-L1 tumor proportion score (TPS) was calculated as the percentage of at least 100 viable tumor cells with complete or partial membrane staining. TPS was reported in three categories (no expression, <1%; low expression, 1-49%; and high expression, ≥50%).
4c3880bb027f159e801041b1021e88e8 Result
Of the 233 cases analyzed, the median age was 60 (range, 34-82 years), 149 (63.9%) patients were female, 167 (71.7%) patients were never-smokers, and 55 (23.6%) patients had stage Ⅲ (50) and Ⅳ (5) disease. Among them, 139 (59.7%) patients had activating EGFR mutations, and 23 (9.9%) patients were KRAS mutant. Proportions in each PD-L1 TPS category were: <1%, 63.9%(149/233); 1-49%, 23.6%(55/233); ≥50%, 12.5%(29/233). Wilcoxon rank sum test(Mann-Whitney U test) revealed that PD-L1 positivity had negative correlation with patient age (p = 0.027), and positive correlation with male (p = 0.001), smoker (p = 0.007), advanced stage (p < 0.001). EGFR-mutated tumors (n= 139) demonstrated lower rates of PD-L1 expression [TPS <1% (72.7%); 1-49% (22.3%); ≥50% (5.0%); P<0.001];meanwhile,KRAS-mutated tumors (n= 23) showed higher rates of PD-L1 expression [TPS <1% (43.5%); 1-49% (30.4%); ≥50% (26.1%); P<0.001].
8eea62084ca7e541d918e823422bd82e Conclusion
This investigation shows that in primary lung adenocarcinoma the PD-L1 expression was significantly associated with younger age, male, smokers, high stagedisease, EGFR wild-type and KRAS mutant. Therefore, it is rational to choose a different checkpoint inhibitor according to the driver gene mutation status and to combine targeted therapies and anti-PD-L1 agents.
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