Clinical Information

Persistent infection with human papillomavirus (HPV) can cause anal cancer, with approximately 90% of all anal cancers being associated with HPV infection. HPV is a small, nonenveloped, double-stranded DNA virus, with a genome of approximately 8000 nucleotides. There are more than 118 different types of HPV and approximately 40 different HPVs that can infect the human anogenital mucosa. However, data suggest that 14 of these types (HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) are considered high-risk (HR) for the development of cervical and anal cancer and precursor lesions. Furthermore, HPV types 16 and 18 have been regarded as the genotypes most closely associated with progression to cancer. HPV-16 is the most carcinogenic and is associated with approximately 60% of all HPV-related cancers, while HPV-18 accounts for approximately 10% to 15% of HPV-related cancers.(1-3)

Sexually transmitted infection with HPV is extremely common, with estimates of up to 75% of all women being exposed to HPV at some point. However, almost all infected patients will mount an effective immune response and clear the infection within 2 years without any long-term health consequences.

DNA testing by real-time polymerase chain reaction (PCR) is a noninvasive method for determining the presence of anal HPV infection. Proper implementation of DNA testing for HPV may:

1. Increase the sensitivity of anal cancer detection

2. Reduce the need for unnecessary biopsy and treatment

Recently, data suggest that individual genotyping for HPV types 16 and 18 can assist in determining appropriate follow-up testing and triaging of patients who are at risk for cervical cancer and may be useful in cases of possible anal cancer. Detection of HRHPV DNA, especially genotypes 16 and 18, may assist in triaging patients and determining appropriate management strategies.