Episomal HPV16 responsible for aggressive and deadly metastatic anal squamous cell carcinoma evidenced in peripheral blood

Archival tissue samples collected longitudinally from a patient who died from HPV16-induced high-grade anal intraepithelial squamous cell carcinoma with vertebral HPV16–positive metastasis were retrospectively analyzed by the Capture-HPV method (Capt-HPV) followed by Next-Generation Sequencing (NGS). Full length nucleotide sequences of the same HPV16 were identified from the initial and second anal biopsy samples, from plasma sample and from vertebral metastasis biopsy. Remarkably, HPV was episomal in each sample. The HPV genome sequence was closest to the HPV16 Qv18158E variant subtype (A1 lineage) exhibiting base substitutions and deletions in 7 and 2 HPV loci, respectively. In conclusion, the powerful Capt-HPV followed by NGS allows evidencing the detailed cartography of tumoral and circulating HPV DNA, giving rise to a unique and unexpected episomal virus molecular status in a context of aggressive carcinoma, underlying the importance of HPV status and its association with clinical features for further prospective studies.