Abstract
BACKGROUND: Like tumor cells, cancer-associated fibroblasts (CAFs) can enter the bloodstream and may function in systemic circulation. METHODS: Circulating CAFs (cCAFs) were isolated from the peripheral blood of head and neck squamous cell carcinoma (HNSCC) patients using CD45 depletion and detected by FAP expression using RT-qPCR. Circulating tumor cells (CTCs) were detected through the expression of epithelial markers (EPCAM, EGFR, and MET). We analyzed the association between cCAF positivity and clinical factors, CTC characteristics, and verified tumor tissue relationships using public datasets. RESULTS: Of the 97 patients, 19.6% were positive for cCAFs and 61.9% for CTCs. cCAF positivity was significantly associated with lymph node metastasis, CTC positivity, and lower EPCAM levels on CTCs. In tumor tissues, FAP expression inversely correlated with EPCAM expression in tumor cells. CONCLUSION: cCAFs may contribute to the survival of CTCs and tumor progression through changes in the characteristics of CTCs.