Abstract
An immunotherapy was found to be effective in achieving long-term survival in some lung cancer (LC) patients. It has emerged to searching for new immune biomarkers for select the best candidates to this therapy. Previously, we confirmed presence of circulating CSCs in LC patients with the highest proportion of EpCAM+/CD133+ in patients with metastatic disease. It suggests that CSCs are responsible for tumor initiation, maintenance and its metastatic potential. However, a role of CSCs in escape of cancer from immunosurveillance is unknown. The aim of the study was to examine the expression of PD-L1 on cancer stem cells (CSCs) in metastatic lymph nodes (LNs) in LC patients.
We identified CSCs in LNs (station 7,10,11) aspirates obtained during EBUS/TBNA procedure. Flow cytometry (FC) with anti-CD133, anti-EpCAM antibodies was applied to identify CSCs; additionally anti-PD-L1 antibody was applied to examine PD-L1 expression on lung CSCs.
Of 21 patients the LNs metastases were confirmed in 11 patients. We noticed presence of PD-L1 on CD133+, EpCAM+ and both CD133+/EpCAM+ cells. A higher percentage of CD133+/EpCAM+/PD-L1+ cells was observed in patients with metastatic in LNs- median value=4.23% than in patients without LNs metastases– median value=0,02%. The highest proportion of PD-L1+ CSCs was found in adenocarcinoma.
We confirmed for the first time the presence of CSCs with expression of PD-L1 in the metastatic LNs what might suggest their immunogenic potential. EBUS/TBNA is commonly used in diagnosis and staging of LC, so the analysis of the cells in metastatic LNs may fit in “immunoscoring” before immunotherapy.
Footnotes
Cite this article as: European Respiratory Journal 2018 52: Suppl. 62, OA3300.
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- Copyright ©the authors 2018