Circulating Tumor Cells in Head and Neck Squamous-Cell Carcinoma Exhibit Distinct Properties Based on Targeted...

The detection of circulating tumor cells (CTCs) using immunoaffinity-based methods often relies on epithelial-related markers, which may bias the selection of CTCs and limit the biological information obtained, depending on the targeted antigens. Herein, we compared the molecular profiles and clinical significance of CTCs based on the expression of epithelial-related markers (EPCAM, EGFR, and MET) in patients with head and neck squamous-cell carcinoma (HNSCC). CTCs were detected using density gradient separation and CD45-negative selection, followed by quantitative PCR for epithelial-related marker expression. Expression profiles of epithelial-mesenchymal transition (EMT)-related (VIM, CDH1, CDH2, SNAI1, ZEB1, ZEB2, and TWIST1) and immune-regulatory (CD274 and PDCD1LG2) genes were compared. Moreover, the association between marker expression and clinical factors was analyzed. Among the 60 patients with CTCs, 48 (80.0%), 20 (33.3%), and 31 (51.7%) were positive for EPCAM, EGFR, and MET, respectively. A significant correlation was observed between CTCs expressing EPCAM and EGFR. CTCs expressing distinct markers showed differing EMT-related and immune-regulatory gene expression. EPCAM+ CTCs were associated with advanced-stage disease, while EGFR+ CTCs were correlated with locoregional relapse and shorter progression-free survival (p = 0.007; hazard ratio = 3.254). Patients with EPCAM/EGFR double-positive CTCs had the poorest prognosis. These findings emphasize the importance of marker selection in liquid biopsy technologies and highlight the need for improved detection methods and the further investigation of CTC biology.