Background: Budding from the plasma membrane of both benign and malign cells, large extracellular vesicles (lEV) are secreted into the blood and are easily accessible for diagnostics. So far, the diagnostic potential for lEV in patients with squamous head and neck cancer (HNSCC) has not been investigated.

Methods: lEV were isolated from the peripheral blood of HNSCC patients and healthy controls by differential centrifugation. Flow cytometry was applied to analyze the expression of EGFR, EPCAM, MUC1 and PD-L1. Information in TNM-status, localization of the tumor, p16 and PD-L1 status was retrieved from patient records. T-statistics, Spearman"s r as well as multiple logistic regression were applied for statistical analysis.

Results: Overall, 66 HNSCC and 11 controls were included. HNSCC showed a significantly higher expression of EGFR and MUC1 in flow cytometry. Multiple logistic regression using EGFR, PD-L1 and EPCAM showed, that Receiver Operator Curves were able to distinguish between control and HNSCC samples (p = 0.003, AUC 0.785 (0.676;0.894)). Concerning PD-L1 status we observeed an increase in PD-L1 signal in patients with higher T-stadium (r = 0.3813, p = 0.002). Similarly, metastasis is associated with an increase of PD-L1 signal (r = 0.3746. P = 0.002), while EGFR signal is decreased in patients with metastasis (r = -0.2436, p = 0.049). MUC1 expression shows a negative association with extranodal extension status (r = -0.3059, p = 0.045).

Conclusion: Analysis of lEV in HNSCC patients is possible. The panel of markers proposed is able to differentiate between cancer patients and controls. Changes in EGFR and PD-L1 expression between patients of low and high tumour burden should be investigated in more detail.

Nein.