Assessment of the total cfDNA and HPV16/18 detection in plasma samples of head and neck squamous cell carcinoma patients

The advantages of the circulating cell-free DNA (cfDNA) methodology are quick results and the possibility of repeated analysis. The main aim of our study was to establish the relationship of the total cfDNA with patients’ clinical characteristics and circulating HPV DNA detection in the blood of patients with head and neck squamous cell carcinoma (HNSCC). The cfDNA level of 200 HNSCC patients in plasma was quantified using TaqMan-based TERT amplification. TaqMan technology was also used for HPV16/18 detection. Additionally, mutations in KRAS and EGFR were investigated. A higher level (p = 0.011) of the total cfDNA was found in patients with oropharyngeal squamous cell carcinoma (OPSCC) (9.60 ± 6.23 ng/ml) in comparison with other HNSCC (7.67 ± 4.44 ng/ml). The level of cfDNA in patients with clinical N2–N3 disease (9.28 ± 6.34 ng/ml) was (p = 0.015) higher than in patients with a clinical N0–N1 disease (7.50 ± 3.69 ng/ml). It was also higher in patients with stage IV (9.16 ± 6.04 ng/ml) compared with stages I–III of cancer (7.26 ± 3.63 ng/ml) (p = 0.011). Analysis of HPV16/18 in plasma revealed that 14% of patients were HPV-positive, the majority of whom had the type HPV16 (96.4%). CfDNA level was comparable in HPV-positive and HPV-negative HNSCC patients, as well in the OPSCC subgroup. Somatic mutations in EGFR and KRAS were not found. A high level of cfDNA is specific for patients with OPSCC. HPV detection in cfDNA does not depend on the cfDNA concentration. Our results prove the diagnostic potential of plasma-based HPV cfDNA tests for the early detection and monitoring of HPV-positive HNSCC.