Maria Ines Figueiredo*, Ana Ladeirinha, Ana Alarcao, ViÂtor Sousa and Lina Carvalho
Introduction: Programmed death-ligand 1 (PD-L1) expression became a routine biomarker to preview response to programmed death-1 (PD-1)/PD-L1 inhibitors, with diverging parameters concerning PD-L1 scoring and variable response to immunotherapy agents. The aim of this study was to evaluate association between PD-L1 expression and immunohistochemistry panel applied in Pathology practice, defining any of those antibodies as biomarkers concurrent in patient’s selection for PD-1/PD-L1 blockade therapy.
Methods: A total of 97 cTNM IIIb/IV staged pulmonary carcinoma biopsies were randomly selected between 2018/2020, after adequate representativeness and PD-L1 expression scored through Dako 22C3 antibody. The panel with cytokeratin 7, thyroid transcription factor 1 (TTF1), cytokeratin 5.6, cluster of differentiation 56 (CD56), periodic acid-Schiff (PAS-D), vimentin expression, and ki-67 labeling index (LI) was considered for retrieving reports and respective archival slides.
Results: PD-L1 expression in tumor cells (TCs) was identified in 56 samples and significantly associated with male gender (p=0.028), vimentin expression (p=0.018) and ki-67 LI>30% (p=0.029). A tendency to PD-L1 positivity came up in lymphocytic-predominant/immune-inflamed stroma (9/10), adenocarcinoma solid subtype (21/23) and CK7-negative squamous cell carcinomas (8/13). When more than 50% TCs expressed PD-L1, the risk of vimentin expression was 3.85 times higher (OR=3.85; p=0.013), and for ki-67 LI>30% the risk was 9.90 times higher (OR=9.90; p=0.033), compared with PD-L1-negative samples.
Conclusion: High proliferation status defined by ki-67 LI>30% and epithelial-mesenchymal transition phenotype verified by vimentin staining analysis might complement PD-L1-positive TCs percentage determination for immunotherapy prescription. These patients will more likely benefit from PD-1/PD-L1 blockade therapy, overcoming the limitations of patient selection based on PD-L1 immunohistochemistry status.
Published Date: 2022-02-22; Received Date: 2022-01-25
