Human papillomavirus and oropharyngeal cancer

Is High-Risk Sexual Behavior a Risk Factor for Oropharyngeal Cancer?

(1) Background: Several lines of evidence established a link between high-risk (HR) sexual behavior (SB), the persistence of human papillomavirus (HPV) DNA in saliva, and the presence of oncogenic HR-HPV subtypes in oropharyngeal squamous cell carcinoma (OPSCC). A highly influential case-control study by D'Souza et al. comparing OPSCC patients and ENT patients with benign diseases (hospital controls) established HR-SB as a putative etiological risk factor for OPSCC. Aiming to replicate their findings in a nested case-control study of OPSCC patients and propensity score (PS)-matched unaffected controls from a large population-based German cohort study, we here demonstrate discrepant findings regarding HR-SB in OPSCC. (2) Methods: According to the main risk factors for HNSCC (age, sex, tobacco smoking, and alcohol consumption) PS-matched healthy controls invited from the population-based cohort study LIFE and HNSCC (including OPSCC) patients underwent interviews, using AUDIT and Fagerström, as well as questionnaires asking for SB categories as published. Afterwards, by newly calculating PSs for the same four risk factors, we matched each OPSCC patient with two healthy controls and compared responses utilizing chi-squared tests and logistic regression. (3) Results: The HNSCC patients and controls showed significant differences in sex distribution, chronologic age, tobacco-smoking history (pack years), and alcohol dependence (based on AUDIT score). However, PS-matching decreased the differences between OPSCC patients and controls substantially. Despite confirming that OPSCC patients were more likely to self-report their first sexual intercourse before age 18, we found no association between OPSCC and HR-SB, neither for practicing oral-sex, having an increased number of oral- or vaginal-sex partners, nor for having casual sex or having any sexually transmitted disease. (4) Conclusions: Our data, by showing a low prevalence of HR-SB in OPSCC patients, confirm findings from other European studies that differ substantially from North American case-control studies. HR-SB alone may not add excess risk for developing OPSCC.

Mate-Pair Sequencing as a Powerful Clinical Tool for the Characterization of Cancers with a DNA Viral Etiology

DNA viruses are known to be associated with a variety of different cancers. Human papillomaviruses (HPV) are a family of viruses and several of its sub-types are classified as high-risk HPVs as they are found to be associated with the development of a number of different cancers. Almost all cervical cancers appear to be driven by HPV infection and HPV is also found in most cancers of the anus and at least half the cancers of the vulva, penis and vagina, and increasingly found in one sub-type of head and neck cancers namely oropharyngeal squamous cell carcinoma. Our understanding of HPVs role in cancer development comes from extensive studies done on cervical cancer and it has just been assumed that HPV plays an identical role in the development of all other cancers arising in the presence of HPV sequences, although this has not been proven. Most invasive cervical cancers have the HPV genome integrated into one or more sites within the human genome. One powerful tool to examine all the sites of HPV integration in a cancer but that also provides a comprehensive view of genomic alterations in that cancer is the use of next generation sequencing of mate-pair libraries produced from the DNA isolated. We will describe how this powerful technology can provide important information about the genomic organization within an individual cancer genome, and how this has demonstrated that HPVs role in oropharyngeal squamous cell carcinoma is distinct from that in cervical cancer. We will also describe why the sequencing of mate-pair libraries could be a powerful clinical tool for the management of patients with a DNA viral etiology and how this could quickly transform the care of these patients.

Mate pair sequencing of oropharyngeal squamous cell carcinomas reveals that HPV integration occurs much less frequently than in cervical cancer

BACKGROUND

Human papillomavirus (HPV) is now recognized to be very important in the pathogenesis of oropharyngeal squamous cell carcinoma (OPSCC). It is not clear yet whether the physical status of HPV in OPSCC is similar to what is found in cervical cancer.

STUDY DESIGN

We performed genome-wide mate pair next generation sequencing from 20 OPSCCs patients, thirteen of which were positive for HPV16 to determine the HPV physical status and its relationship to HPV oncogene E6 and E7 expression.

RESULTS

This high throughput approach detected HPV integration events and also determined the bridged HPV coverage in each sample. Two of the HPV16-positive OPSCCs had HPV integration and one of the HPV16-negative OPSCCs had an HPV26 integration. We mapped the site of integration in the HPV genome in all integration events and the integrations were located at E1, E5, E6 and L2 region respectively. One HPV positive OPSCC had two integration events but also had a very high bridged HPV coverage, while the other two just had HPV integrated into the human genome.

CONCLUSION

Our results are thus different from what is routinely observed in cervical cancer where HPV is almost always integrated into the human genome with loss of episomal HPV sequences. Thus more investigation should be carried out to study how episomal HPV alone can contribute to the development of most OPSCCs.

Next-generation treatment strategies for human papillomavirus-related head and neck squamous cell carcinoma: where do we go?

Oncogenic human papillomavirus (HPV) is currently recognised as a major risk factor for the development of head and neck squamous cell carcinomas (HNSCC). HPV is mostly detected in tumours arising from the oropharynx and more specifically from the tonsil. HPV-related tumours display clinical and molecular characteristics that are distinct from HPV-unrelated tumours, which are generally induced by alcohol and tobacco abuse. Detection of biologically active HPV in HNSCC has prognostic relevance, which warrants the separate classification of HPV-induced tumours and is a prerequisite for further optimisation of treatment protocols for this distinct group. Current guidelines for the treatment of oropharyngeal squamous cell carcinoma (OPSCC) have not incorporated specific treatment modalities for HPV-related tumours. The development of such treatment options is still in a preclinical phase or in early clinical trials. Recent data on treatment response of OPSCC have been obtained by retrospectively analysing HPV-status and indicate that patients with HPV-related tumours show a favourable prognosis, independent of the type of treatment. These patients may benefit from de-intensified treatment, which should be assessed in prospective clinical trials. The development and future use of new antiviral and immunomodulatory therapeutics may be instrumental in this approach to improve survival rates and decrease disease-and-treatment-related morbidity. In this review we will focus on present therapeutic HPV-targeting strategies and discuss future directions for de-intensified treatment of HPV-positive HNSCC.