Human papillomavirus in head and neck tumors: epidemiological, molecular and clinical aspects

Modifiable risk behaviors in patients with head and neck cancer

BACKGROUND

Use of tobacco products, excessive alcohol consumption, and high-risk sexual behaviors increase the risk of developing head and neck cancer and impacts treatment effectiveness after diagnosis. This study examined smoking and engagement in other modifiable behavioral risk factors and human papillomavirus (HPV) status in patients with head and neck cancer in order to facilitate identification and foster development of targeted interventions in high-risk patients.

METHODS

Participants were 102 patients with head and neck cancer at a large urban cancer center who completed a self-report background and health questionnaire and provided a saliva sample for determination of the long-acting nicotine metabolite cotinine.

RESULTS

Compared with former and never-smokers, current smokers were less educated, less likely to be married or living with a partner, and consumed more alcohol. Cotinine analysis indicated that 4 of 16 (25%) patients who denied past-month cigarette use misrepresented their true smoking status. Of patients with oropharyngeal cancer, 74% were confirmed as HPV-positive, and compared with HPV-negative patients, they were younger, more likely to be married/partnered and of Caucasian race, and reported more past vaginal and oral sexual partners. Only one-third of HPV-positive patients were aware of their HPV disease status.

CONCLUSIONS

Cigarette smoking is associated with engagement in other modifiable risk factors in patients with head and neck cancer. Self-report measures of smoking may not accurately depict true smoking status. HPV-positive cancer patients were more likely to endorse a history of multiple sexual partners. Regular screening and targeted interventions for these distinct risk factors are warranted.

Nucleotide and phylogenetic analysis of human papillomavirus types 6 and 11 isolated from recurrent respiratory papillomatosis in Brazil

There are few studies about the distribution of natural molecular variants of low-risk HPVs. Our aim was to evaluate the E6 early gene variability among HPV-6 and HPV-11 isolates detected in recurrent respiratory papillomatosis (RRP) samples obtained in a cohort of Brazilian patients. We also performed a phylogenetic analysis in order to compare nucleotide sequences identified in our study with previously reported isolates from different anatomic sites (laryngeal papillomas, genital warts, cervical cancer and anal swabs) obtained from other parts of the world to determine the phylogenetic relationships of variants detected in Brazil. The complete coding region of the E6 gene of 25 samples was cloned and sequenced: 18 isolates of HPV-6 (72%) and 7 isolates of HPV-11 (28%). A total of four different HPV-6 genomic variants and two HPV-11 genomic variants was identified. It was not possible to correlate specific variants with disease severity. Phylogenetic trees for both HPV types were constructed enclosing both E6 sequences detected in our study and formerly published sequences. In both phylogenetic trees, the sequences from Brazil did not group together. We could not establish a geographical association between HPV-6 or HPV-11 variants, unlike HPV-16 and HPV-18.

Loss of adhesion/growth-regulatory galectin-9 from squamous cell epithelium in head and neck carcinomas

Galectins are potent effectors of cell adhesion and growth regulation. Their expression as comples network necessitates systematic study of each member of this family. Toward this aim, we here focus on the tandem-repeat-type galectin-9. Its presence is monitored in normal squamous epithelium of the head and neck, the surgical margin, and four types of squamous cell carcinoma. Lectin presence was detected in cells of the basal layer of the epithelium. All galectin-9-negative epithelia showed aberrant positivity for keratins 14 and 19. The surgical margin presented either a normal pattern of galectin-9 and keratin presence or a mosaic-like presence/absence of galectin-9 and aberrant expression of both keratins 14 and 19. All studied specimens of squamous cell carcinoma were negative for galectin-9. When biotinylated galectin-9, or its N-terminal domain, was tested, no significant tissue reactivity for both probes was observed. Neuraminidase treatment generated reactivity to the N-domain. In conclusion, galectin-9 is expressed in the majority of samples of normal epithelium, along with regular presence of keratins 14 or 19. This lectin can represent a potential marker of normality in the cases of the studied squamous cell epithelia.

Papillomavirus E5: the smallest oncoprotein with many functions

Papillomaviruses (PVs) are established agents of human and animal cancers. They infect cutaneous and mucous epithelia. High Risk (HR) Human PVs (HPVs) are consistently associated with cancer of the uterine cervix, but are also involved in the etiopathogenesis of other cancer types. The early oncoproteins of PVs: E5, E6 and E7 are known to contribute to tumour progression. While the oncogenic activities of E6 and E7 are well characterised, the role of E5 is still rather nebulous. The widespread causal association of PVs with cancer makes their study worthwhile not only in humans but also in animal model systems. The Bovine PV (BPV) system has been the most useful animal model in understanding the oncogenic potential of PVs due to the pivotal role of its E5 oncoprotein in cell transformation. This review will highlight the differences between HPV-16 E5 (16E5) and E5 from other PVs, primarily from BPV. It will discuss the targeting of E5 as a possible therapeutic agent.

High-risk human papillomavirus (HPV) screening and detection in healthy patient saliva samples: a pilot study

Background

The human papillomaviruses (HPV) are a large family of non-enveloped DNA viruses, mainly associated with cervical cancers. Recent epidemiologic evidence has suggested that HPV may be an independent risk factor for oropharyngeal cancers. Evidence now suggests HPV may modulate the malignancy process in some tobacco- and alcohol-induced oropharynx tumors, but might also be the primary oncogenic factor for inducing carcinogenesis among some non-smokers. More evidence, however, is needed regarding oral HPV prevalence among healthy adults to estimate risk. The goal of this study was to perform an HPV screening of normal healthy adults to assess oral HPV prevalence.

Methods

Healthy adult patients at a US dental school were selected to participate in this pilot study. DNA was isolated from saliva samples and screened for high-risk HPV strains HPV16 and HPV18 and further processed using qPCR for quantification and to confirm analytical sensitivity and specificity.

Results

Chi-square analysis revealed the patient sample was representative of the general clinic population with respect to gender, race and age (p < 0.05). Four patient samples were found to harbor HPV16 DNA, representing 2.6% of the total (n = 151). Three of the four HPV16-positive samples were from patients under 65 years of age and all four were female and Hispanic (non-White). No samples tested positive for HPV18.

Conclusions

The successful recruitment and screening of healthy adult patients revealed HPV16, but not HPV18, was present in a small subset. These results provide new information about oral HPV status, which may help to contextualize results from other studies that demonstrate oral cancer rates have risen in the US among both females and minorities and in some geographic areas that are not solely explained by rates of tobacco and alcohol use. The results of this study may be of significant value to further our understanding of oral health and disease risk, as well as to help design future studies exploring the role of other factors that influence oral HPV exposure, as well as the short- and long-term consequences of oral HPV infection.

Role of molecular markers in the management of head and neck cancers

PURPOSE OF REVIEW

Head and neck squamous cell carcinoma (HNSCC) is the fifth most common cancer worldwide. Despite advances in treatment, the prognosis remains poor. HNSCC comprise a wide spectrum of neoplasms with different tumor biologies, prognosis and response to therapies. Current tumor classification is based on morphology and anatomic distribution, which leads to a homogeneous treatment for different diseases. Moreover, traditional diagnostic methods such as clinical assessment, histopathological examination, and imaging techniques are limited in their capacity to provide information on prognosis and decision making.

RECENT FINDINGS

Molecular markers have increased the understanding of the pathogenesis of head and neck cancer because they give increasing insight into tumor biology, prognosis, and response to therapy. The practical application of these discoveries is beginning to assist greatly in the evaluation and treatment of HNSCC to achieve a more personalized and effective approach.

SUMMARY

This article focuses on the molecular markers that have already been extensively studied such as epidermal growth factor receptor and human papillomavirus as well as those that offer potential for personalized therapy such as HIF-1 and ERCC-1. The ideal biomarker should be assayed accurately and easily, highly specific, and cost effective. Thus, a validation is required before their implementation into clinical guidelines.

HPV-DNA integration and carcinogenesis: putative roles for inflammation and oxidative stress

HPV-DNA integration into cellular chromatin is usually a necessary event in the pathogenesis of HPV-related cancer; however, the mechanism of integration has not been clearly defined. Breaks must be created in both the host DNA and in the circular viral episome for integration to occur, and studies have shown that viral integration is indeed increased by the induction of DNA double strand breaks. Inflammation generates reactive oxygen species, which in turn have the potential to create such DNA strand breaks. It is plausible that these breaks enable a greater frequency of HPV-DNA integration, and in this way contribute to carcinogenesis. Consistent with this idea, co-infections with certain sexually transmitted diseases cause cervical inflammation, and have also been identified as cofactors in the progression to cervical cancer. This article examines the idea that inflammation facilitates HPV-DNA integration into cellular chromatin through the generation of reactive oxygen species, thereby contributing to carcinogenesis.