HPV Biomarkers in Oral and Blood-Derived Body Fluids in Head and Neck Cancer Patients

Oral HPV DNA and circulating tumor (ct) HPV DNA in plasma were evaluated as potential biomarkers for HPV-associated head and neck cancer (HNC). Samples from HNC patients (n = 132), including 23 oropharyngeal cancers (OPC), and non-HNC controls (n = 10) were analyzed. HPV status was determined using a multiplex bead-based test (E7-MPG) applied to formalin-fixed paraffin-embedded (FFPE) tissues (n = 90), plasma (n = 141), gargle samples (n = 141), and oral swabs (n = 142). HPV DNA was detected in 25.8% of HNC tissues, 12% of plasma samples, 20.6% of gargles and 7% of oral swabs with HPV16 as the most prevalent genotype. Among OPC cases, HPV16 DNA was found in 71.4% of FFPE samples. High concordance was observed between paired OPC tissues and plasma (91.3%) or gargles (95.2%), with moderate concordance for oral swabs (59.1%). Gargle samples alone demonstrated a 100% detection rate for HPV16-positive OPC, regardless of the cT stage, outperforming plasma (86.7%). Combined oral gargle and plasma analyses detected all HPV-positive OPC cases (7/7) at the early cT1 stage. These findings highlight the limited involvement of HPV in non-oropharyngeal HNC compared to OPC, and support gargle and plasma samples as minimally invasive diagnostic tools for detecting HPV-associated OPC.