Related Experiment Video
Updated: Nov 14, 2025
Using 22C3 Anti-PD-L1 Antibody Concentrate on Biopsy and Cytology Samples from Non-small Cell Lung Cancer Patients
Published on: September 25, 2018
Heterogeneity of PD-L1 expression in lung adenocarcinoma metastasis is related to histopathological subtypes
Fabien Forest1, François Casteillo2, Vanessa Da Cruz3
1Centre Hospitalier Universitaire de Saint Etienne, Hôpital Nord, Department of Pathology, Avenue Albert Raimond, 42055 Saint Etienne, France; University Hospital of Saint Etienne, North Hospital, Molecular Biology of Solid Tumours Unit, Avenue Albert Raimond, 42055 Saint Etienne, France; Centre Hospitalier Universitaire de Saint Etienne, Hôpital Nord, Department of Neurosurgery, Avenue Albert Raimond, 42055 Saint Etienne, France; Corneal Graft Biology, Engineering, and Imaging Laboratory, BiiGC, EA2521, Federative Institute of Research in Sciences and Health Engineering, Faculty of Medicine, Jean Monnet University, Saint-Etienne, France.
Objectives:
The heterogeneity of PD-L1 expression and its relationship with histopathological subtype has recently been shown on primary tumor but has not been evaluated on metastases. The aim of our work is to analyze PD-L1 expression within each histopathological pattern on resected metastases.
Material And Methods:
136 patients were included in this retrospective study. Immunohistochemistry was performed with 22C3 laboratory-developed test. The Tumor Proportion Score was evaluated on each subtype.
Results:
The most frequent major histopathological subtype was solid (n = 69, 50.7 %), followed by acinar (n = 37, 27.2 %), micropapillary (n = 14, 10.3 %) and papillary (n = 10, 7.3 %). Mean percentage of PD-L1 expression for each subtype was at 28+/-4.8 % for solid subtype, 5.3+/-1.9 % for acinar subtype, 5+/-1.9 % for papillary subtype and 23.6+/-4.1 % for micropapillary subtype. Mean percentage of PD-L1 expression was different between solid pattern and acinar pattern (p < 0.001), solid pattern and papillary pattern (p = 0.007), micropapillary pattern and acinar pattern (p < 0.001) and micropapillary pattern and papillary pattern (p = 0.015).
Conclusion:
To conclude, we have showed firstly that several patterns are present in metastases of lung adenocarcinoma, secondly that the evaluation of patterns and PD-L1 stain on different patterns is reproducible, thirdly that pattern heterogeneity is related to PD-L1 staining, fourthly that in metastatic lung adenocarcinoma with at least two patterns, solid and micropapillary subtypes have higher levels of PD-L staining, fifthly that PD-L1 heterogeneity between different patterns is not a rare event. These results might explain discrepancies of PD-L1 results between biopsies and surgical samples and the fact that some patients might respond to checkpoint inhibitors even though PD-L1 expression is low or absent.
