HPVs are a group of circular, double-stranded DNA viruses that infect epithelial cells. More than 100
different genotypes of HPV [186] have been described; of these, a subset infects the anogenital area, and
within this subset, the individual types are classified as either high risk or low risk. High-risk HPVs can
cause cancerous lesions, while low-risk HPVs do not [187]. An important difference between high- and
low-risk HPVs is that high-risk HPVs show a greater tendency to integrate into the host genome, thereby
causing high-grade lesions and cancer, while low-risk types are preferentially maintained as extrachro‐
mosomal circular episomes