SAMHD1 and head and neck cancer: Finally, we demonstrate that the growth of UMSCC104 cells, an HPV16-positive head and neck cancer cell line containing episomal viral genomes, is attenuated more than other head and neck cancer cell lines following endothall treatment, and SAMHD1 and E2 recruitment to the viral genome is increased by endothall treatment of UMSCC104 cells.