Epithelial-Mesenchymal Transition Status of Circulating Tumor Cells Is Associated With Tumor Relapse in Head and Neck Squamous Cell Carcinoma

Background/Aim: We aimed to elucidate the clinical implication of the epithelial-mesenchymal plasticity of circulating tumor cells (CTCs) in patients with head and neck squamous cell carcinoma (HNSCC). Patients and Methods: CTCs isolated from 44 patients with non-recurrent/metastatic HNSCC and 42 with recurrent/metastatic (R/M) HNSCC were classified into four epithelial-mesenchymal transition (EMT) statuses based on the expression of epithelial (keratin 19) and mesenchymal (vimentin) markers and the relationships between EMT status in CTCs and clinical factors were investigated. Results: E+M- CTC phenotype was more frequent in patients without recurrence/metastasis (p=0.0468) and was also more frequent in those with a complete response (p=0.0346). The E+M+ phenotype constituted the major proportion of the CTCs detected in patients with R/M HNSCC (p=0.0374). Conclusion: CTCs may play unique roles at various stages of metastasis through transitioning from epithelial to mesenchymal phenotypes.