American Board of Internal Medicine (ABIM) Certification Practice Exam

To diagnose human papillomavirus infection in head and neck cancer, which test is commonly used?

1. PCR testing

2. p16 immunohistochemistry testing

3. Serological testing

4. CT scan evaluation

The correct answer is: p16 immunohistochemistry testing

The use of p16 immunohistochemistry testing is a reliable and commonly employed method for diagnosing human papillomavirus (HPV) infection in cases of head and neck cancer, particularly oropharyngeal squamous cell carcinoma. The presence of p16, a tumor suppressor protein, serves as a surrogate marker indicating the oncogenic activity of HPV. When HPV infects epithelial cells, it often leads to the upregulation of p16 due to the viral proteins E6 and E7 interfering with the normal regulation of cell cycle pathways. Testing for p16 is beneficial because it is relatively straightforward and can be performed on tissue obtained from biopsy specimens. It provides both diagnostic and prognostic information, as HPV-positive head and neck cancers tend to have a more favorable response to treatment compared to their HPV-negative counterparts. In contrast, while PCR testing can detect HPV DNA and is useful in certain contexts, it is not routinely used in the clinical setting for diagnosing HPV-associated head and neck cancers. Serological testing for HPV antibodies is less specific and not considered standard practice for diagnosing the type of HPV involved in these malignancies. CT scan evaluations are primarily imaging modalities and do not provide definitive information regarding HPV infection status. Thus, the association of p16