Circulating Biomarkers in Head and Neck Cancer

Head and neck cancer remains one of the leading causes of death worldwide. Liquid biopsy has emerged as a promising tool for detecting cancer and monitoring the disease status. Circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and exosomal microRNAs (miRNAs) warrant close attention because of their apparent clinical implications. Circulating biomarkers have led to a paradigm shift and opened up novel therapeutic avenues, starting a new era of precision medicine. An increasing number of studies suggest that circulating biomarkers can be used to detect cancer, plan treatment, monitor treatment response, and assess the prognosis. However, no validated circulating biomarkers have been integrated into clinical practice for head and neck cancer despite their potential clinical utilities. This chapter focuses on the recent advances in studying and utilizing circulating biomarkers in the context of head and neck cancer, together with the limitations and key clinical applications.