Circulating Tumor DNA in Head and Neck Squamous Cell Carcinoma

SIMPLE SUMMARY: Head and Neck Squamous Cell Carcinomas (HNSCCs) are cancers that originate from cells of the head and neck region, including the mouth, nose, and throat. The diversity of these cell types is also mirrored by the high number of different mutations that promote cancer development and progression. For the clinical management of this disease, it is important to identify biomarkers that allow early detection or predict relapse and resistance to therapy. A non-invasive way to monitor these markers over time are so called liquid biopsies, which mostly refers to the detection and analysis of tumor cells or cell-free DNA (cfDNA) in the blood of patients. This review summarizes our current understanding of HNSCC genetics and discusses how the detection of genetic variation in the cfDNA of HNSCC patients can be used to monitor disease and guide therapy. ABSTRACT: Tumors shed cell-free DNA (cfDNA) into the plasma. “Liquid biopsies” are a diagnostic test to analyze cfDNA in order to detect minimal residual cancer, profile the genomic tumor landscape, and monitor cancers non-invasively over time. This technique may be useful in patients with head and neck squamous cell carcinoma (HNSCC) due to genetic tumor heterogeneity and limitations in imaging sensitivity. However, there are technical challenges that need to be overcome for the widespread use of liquid biopsy in the clinical management of these patients. In this review, we discuss our current understanding of HNSCC genetics and the role of cfDNA genomic analyses as an emerging precision diagnostic tool.