Diagnostic accuracy of serum antibodies to human papillomavirus type 16 early antigens in the detection of human papillomavirus-related oropharyngeal cancer

Diagnostic accuracy of HPV16 early antigen serology for HPV-driven oropharyngeal cancer is independent of age and sex

A growing proportion of head and neck cancer (HNC), especially oropharyngeal cancer (OPC), is caused by human papillomavirus (HPV). There are several markers for HPV-driven HNC, one being HPV early antigen serology. We aimed to investigate the diagnostic accuracy of HPV serology and its performance across patient characteristics. Data from the VOYAGER consortium was used, which comprises five studies on HNC from North America and Europe. Diagnostic accuracy, that is, sensitivity, specificity, Cohen's kappa and correctly classified proportions of HPV16 E6 serology, was assessed for OPC and other HNC using p16INK4a immunohistochemistry (p16), HPV in situ hybridization (ISH) and HPV PCR as reference methods. Stratified analyses were performed for variables including age, sex, smoking and alcohol use, to test the robustness of diagnostic accuracy. A risk-factor analysis based on serology was conducted, comparing HPV-driven to non-HPV-driven OPC. Overall, HPV serology had a sensitivity of 86.8% (95% CI 85.1-88.3) and specificity of 91.2% (95% CI 88.6-93.4) for HPV-driven OPC using p16 as a reference method. In stratified analyses, diagnostic accuracy remained consistent across sex and different age groups. Sensitivity was lower for heavy smokers (77.7%), OPC without lymph node involvement (74.4%) and the ARCAGE study (66.7%), while specificity decreased for cases with <10 pack-years (72.1%). The risk-factor model included study, year of diagnosis, age, sex, BMI, alcohol use, pack-years, TNM-T and TNM-N stage. HPV serology is a robust biomarker for HPV-driven OPC, and its diagnostic accuracy is independent of age and sex. Future research is suggested on the influence of smoking on HPV antibody levels.

Immune Responses in Oral Papillomavirus Clearance in the MmuPV1 Mouse Model

Human papillomavirus (HPV)-induced oropharyngeal cancer now exceeds HPV-induced cervical cancer, with a noticeable sex bias. Although it is well established that women have a more proficient immune system, it remains unclear whether immune control of oral papillomavirus infections differs between sexes. In the current study, we use genetically modified mice to target CCR2 and Stat1 pathways, with the aim of investigating the role of both innate and adaptive immune responses in clearing oral papillomavirus, using our established papillomavirus (MmuPV1) infection model. Persistent oral MmuPV1 infection was detected in Rag1ko mice with T and B cell deficiencies. Meanwhile, other tested mice were susceptible to MmuPV1 infections but were able to clear the virus. We found sex differences in key myeloid cells, including macrophages, neutrophils, and dendritic cells in the infected tongues of wild type and Stat1ko mice but these differences were not observed in CCR2ko mice. Intriguingly, we also observed a sex difference in anti-MmuPV1 E4 antibody levels, especially for two IgG isotypes: IgG2b and IgG3. However, we found comparable numbers of interferon-gamma-producing CD8 T cells stimulated by E6 and E7 in both sexes. These findings suggest that males and females may use different components of innate and adaptive immune responses to control papillomavirus infections in the MmuPV1 mouse model. The observed sex difference in immune responses, especially in myeloid cells including dendritic cell (DC) subsets, may have potential diagnostic and prognostic values for HPV-associated oropharyngeal cancer.

Peripheral surrogates of tumor burden to guide chemotherapeutic and immunotherapeutic strategies for HPV-associated malignancies

With the rapid adoption of immunotherapy into clinical practice for HPV-associated malignancies, assessing tumor burden using "liquid biopsies" would further our understanding of clinical outcomes mediated by immunotherapy and allow for tailoring of treatment based on real-time tumor dynamics. In this review, we examine translational studies on peripheral surrogates of tumor burden derived from peripheral blood in HPV-associated malignancies, including levels and methylation of circulating tumor DNA (ctDNA), miRNA derived from extracellular vesicles, circulating tumor cells (CTCs), and HPV-specific antibodies and T cell responses. We review their utility as prognostic and predictive biomarkers of response to chemotherapy and radiation, with a focus on how they may inform and guide immunotherapies to treat locally advanced and metastatic HPV-associated malignancies. We also highlight unanswered questions that must be addressed to translate and integrate these peripheral tumor biomarkers into the clinic.

The Tumor-Specific Immune Landscape in HPV+ Head and Neck Cancer

Human papillomaviruses (HPVs) are the causative agent of several anogenital cancers as well as head and neck cancers, with HPV+ head and neck squamous cell carcinoma (HNSCC) becoming a rapidly growing public health issue in the Western world. Due its viral etiology and potentially its subanatomical location, HPV+ HNSCC exhibits an immune microenvironment which is more inflamed and thus distinct from HPV-negative HNSCC. Notably, the antigenic landscape in most HPV+ HNSCC tumors extends beyond the classical HPV oncoproteins E6/7 and is extensively targeted by both the humoral and cellular arms of the adaptive immune system. Here, we provide a comprehensive overview of HPV-specific immune responses in patients with HPV+ HNSCC. We highlight the localization, antigen specificity, and differentiation states of humoral and cellular immune responses, and discuss their similarities and differences. Finally, we review currently pursued immunotherapeutic treatment modalities that attempt to harness HPV-specific immune responses for improving clinical outcomes in patients with HPV+ HNSCC.

Is 2045 the best we can do? Mitigating the HPV-related oropharyngeal cancer epidemic

INTRODUCTION

Oropharyngeal cancer (OPC) will be among the most common cancers in men by 2045 due to a rapid rise in human papillomavirus (HPV)-related OPC. Those who survive their cancer often suffer life-long treatment effects and early death. HPV vaccination could prevent virtually all HPV-related cancers but is not an effective preventive strategy for those already exposed. Without a dramatic increase in vaccine uptake in the U.S., HPV vaccination will have a negligible effect on OPC incidence through 2045 and no substantial impact until 2060. Additionally, targeted screening for earlier diagnosis may soon be feasible for those inadequately protected by vaccination.

AREAS COVERED

PubMed search for English-language articles related to incidence, screening, and prevention of HPV-related malignancies, focused on OPC in the U.S.

EXPERT OPINION

HPV-related OPC incidence will continue to increase for the foreseeable future with prophylactic vaccination offering no substantial public health impact for decades. Consequently, we must rapidly increase vaccination rates and develop screening methods to identify high-risk individuals. Such individuals would be eligible for potential preventive treatments and screening to diagnose early-stage HPV-related OPC allowing less morbid treatments. These methods will bridge the population into an era of decreasing incidence after vaccination takes effect.

Defining HPV-specific B cell responses in patients with head and neck cancer

Tumours often contain B cells and plasma cells but the antigen specificity of these intratumoral B cells is not well understood^1-8. Here we show that human papillomavirus (HPV)-specific B cell responses are detectable in samples from patients with HPV-positive head and neck cancers, with active production of HPV-specific IgG antibodies in situ. HPV-specific antibody secreting cells (ASCs) were present in the tumour microenvironment, with minimal bystander recruitment of influenza-specific cells, suggesting a localized and antigen-specific ASC response. HPV-specific ASC responses correlated with titres of plasma IgG and were directed against the HPV proteins E2, E6 and E7, with the most dominant response against E2. Using intratumoral B cells and plasma cells, we generated several HPV-specific human monoclonal antibodies, which exhibited a high degree of somatic hypermutation, consistent with chronic antigen exposure. Single-cell RNA sequencing analyses detected activated B cells, germinal centre B cells and ASCs within the tumour microenvironment. Compared with the tumour parenchyma, B cells and ASCs were preferentially localized in the tumour stroma, with well-formed clusters of activated B cells indicating ongoing germinal centre reactions. Overall, we show that antigen-specific activated and germinal centre B cells as well as plasma cells can be found in the tumour microenvironment. Our findings provide a better understanding of humoral immune responses in human cancer and suggest that tumour-infiltrating B cells could be harnessed for the development of therapeutic agents.

Screening for HPV-related oropharyngeal, anal, and penile cancers in middle-aged men: Initial report from the HOUSTON clinical trial

BACKGROUND

The Human papillomavirus (HPV)-related Oropharyngeal and Uncommon Cancers Screening Trial of Men (HOUSTON) was designed to determine the prevalence of IgG antibodies to HPV type 16 E proteins (HPV16EAbs), to screen for persistence of HPV and/or detect HPV-related premalignancies and cancers, and to assess acceptance of screening among middle-aged men.

METHODS

HOUSTON consists of a cross-sectional study and a longitudinal cohort study of men aged 50-64 years. Serologic HPV16EAb status and oral rinse HPV16 status were determined. All HPV16EAb-positive (HPV16EAb+) men and a matched cohort of HPV16EAb-negative (HPV16EAb-) men as well as all oral rinse HPV16-positive (HPV16+) men were included in the longitudinal study (blinded to their results) and underwent oropharyngeal screening every 6 months as well as one-time anal and penile screening.

RESULTS

Of 553 men enrolled in the cross-sectional study, six (1.1%) were HPV16EAb+ (two were also oral rinse HPV16+), and 41 (7.4%) were HPV16EAb- but oral rinse HPV16+. These 47 men, along with five matched controls, were invited to participate in the longitudinal study, and 42 (81%) agreed and completed baseline in-person screening, with 93% and 90% completeing 6-month and 12-month follow-up visits. One HPV16EAb+ (also oral rinse HPV16+) man, who declined participation in the longitudinal study, presented 4 months after enrollment with an early-stage HPV16-related pharyngeal cancer. Additionally, one HPV16EAb+ (oral rinse HPV16-) man and two oral rinse HPV16+ (HPV16EAb-) men were diagnosed with oncogenic HPV-associated anal dysplasia.

CONCLUSIONS

This biomarker panel deserves further prospective study to explore potential utility for HPV-related cancer screening among men.

Sensitivity and Specificity of Human Papillomavirus (HPV) 16 Early Antigen Serology for HPV-Driven Oropharyngeal Cancer: A Systematic Literature Review and Meta-Analysis

Simple Summary

Serum antibodies against human papillomavirus 16 (HPV16) proteins are associated with HPV-driven oropharyngeal cancer (HPV-OPC). The HPV status of OPC cases is clinically relevant because patients with HPV-OPC show improved survival and treatment response compared to tobacco- or alcohol-induced OPC. In clinical settings, molecular HPV tumor status is usually determined by tissue-based methods detecting molecular markers, such as viral nucleic acids or p16 overexpression. Antibodies against HPV16 in peripheral blood were shown to be very accurate in determining the molecular HPV tumor status in multiple studies. In this work, we reviewed and summarized the available literature on the performance of HPV16 serology for E2, E6 and E7 antibodies to determine molecular HPV tumor status in OPC cases in comparison with tissue-based reference methods. We calculated summary estimates across different studies for sensitivity and specificity, and we investigated factors influencing test performance.

Abstract

Antibodies against HPV16 early proteins have been shown to be promising biomarkers for the identification of HPV-driven oropharyngeal cancer (HPV-OPC) among OPC cases in multiple studies. A systematic literature search was performed to identify original research articles comparing HPV early antigen serology with established reference methods to determine molecular HPV tumor status. Random-effects models were used to calculate summary estimates for sensitivity and specificity of HPV16 E2, E6 and E7 serology for HPV-OPC. Subgroup analyses were performed to explore heterogeneity across studies and describe variables associated with test performance. We identified n = 23 studies meeting all eligibility criteria and included these in the meta-analysis. E6 serology showed the best performance with pooled sensitivity and specificity estimates of 83.1% (95% confidence interval (CI) 72.5–90.2%) and 94.6% (95% CI 89.0–97.4%), respectively, while E2 and E7 serological assays were highly specific (E2: 92.5% (95% CI 79.1–97.6%); E7: 88.5% (95% CI 77.9–94.4%)) but moderately sensitive (E2: 67.8% (95% CI 58.9–75.6%); E7: 67.0% (95% CI 63.2–70.6%)). Subgroup analyses revealed increased pooled sensitivity for bacterially (89.9% (95% CI 84.5–93.6%)) vs. in vitro expressed E6 antigen (55.3% (95% CI 41.0–68.7%)), while both showed high specificity (95.2% (95% CI 93.0–96.7%) and 91.1% (95% CI 46.6–99.2%), respectively). Pooled specificity estimates for HPV16 E2, E6 and E7 serology were significantly lower in studies utilizing HPV DNA PCR as the only molecular reference method compared to those using a combination of any two reference methods (HPV DNA, RNA, in situ hybridization (ISH), p16 immunohistochemistry (IHC)), or histopathological reference methods (ISH or p16 IHC) as stand-alone marker. In conclusion, HPV16 E6 seropositivity is a highly sensitive and specific biomarker for HPV-OPC. However, its performance differs between serological assays and depends on molecular reference methods.

Investigating the association between serum human papillomavirus type 16 E7 antibodies and risk of head and neck cancer

Human papillomavirus (HPV) is recognized as a major cause of oropharyngeal cancer (OPC) in Western countries. Less is known regarding its contribution to the OPC occurring in Asia. The current study aimed to investigate the association between antibody responses to HPV16 E7 and head and neck cancer (HNC) risk in a hospital‐based case–control study conducted in Taiwan with 693 HNC cases and 1,035 controls. A positive association was observed between seropositivity to HPV16 E7 and OPC risk, whereas no significant association was found in the non‐OPC cases. The increased OPC risk associated with seropositivity to HPV16 E7 was more significant among nonbetel quid or noncigarette users. Seropositivity to HPV16 E7 showed moderate agreement with P16 expression in OPC. OPC patients that were seropositive to HPV16 E7 or p16 positive were more highly educated and less likely to use alcohol, betel quids, and cigarettes compared to HPV16 E7 seronegative or p16 negative OPC patients. Furthermore, patients with p16 positive OPC were more likely to be women compared to patients with p16 negative OPC, likely owing to the low prevalence of alcohol, betel quid, and cigarette users among women. Overall, this study suggested that similar to Western countries, HPV may also be an important risk factor of OPC in Taiwan. With the declining consumption of betel quids and cigarettes in Taiwan, a higher percentage of OPC cases in Taiwan will be attributed to HPV in the future. Public health measures, including HPV vaccination, need to be implemented to prevent the occurrence of HPV‐positive OPC.

The current study found a a positive association between seropositivity to HPV16 E7 and oropharyngeal cancer risk. This study suggested that similar to Western countries, HPV may also be an important risk factor of OPC in Taiwan.

Blood-based biomarkers of human papillomavirus-associated cancers: A systematic review and meta-analysis

BACKGROUND

Despite the significant societal burden of human papillomavirus (HPV)-associated cancers, clinical screening interventions for HPV-associated noncervical cancers are not available. Blood-based biomarkers may help close this gap in care.

METHODS

Five databases were searched, 5687 articles were identified, and 3631 unique candidate titles and abstracts were independently reviewed by 2 authors; 702 articles underwent a full-text review. Eligibility criteria included the assessment of a blood-based biomarker within a cohort or case-control study.

RESULTS

One hundred thirty-seven studies were included. Among all biomarkers assessed, HPV-16 E seropositivity and circulating HPV DNA were most significantly correlated with HPV-associated cancers in comparison with cancer-free controls. In most scenarios, HPV-16 E6 seropositivity varied nonsignificantly according to tumor type, specimen collection timing, and anatomic site (crude odds ratio [cOR] for p16+ or HPV+ oropharyngeal cancer [OPC], 133.10; 95% confidence interval [CI], 59.40-298.21; cOR for HPV-unspecified OPC, 25.41; 95% CI, 8.71-74.06; cOR for prediagnostic HPV-unspecified OPC, 59.00; 95% CI, 15.39-226.25; cOR for HPV-unspecified cervical cancer, 12.05; 95% CI, 3.23-44.97; cOR for HPV-unspecified anal cancer, 73.60; 95% CI, 19.68-275.33; cOR for HPV-unspecified penile cancer, 16.25; 95% CI, 2.83-93.48). Circulating HPV-16 DNA was a valid biomarker for cervical cancer (cOR, 15.72; 95% CI, 3.41-72.57). In 3 cervical cancer case-control studies, cases exhibited unique microRNA expression profiles in comparison with controls. Other assessed biomarker candidates were not valid.

CONCLUSIONS

HPV-16 E6 antibodies and circulating HPV-16 DNA are the most robustly analyzed and most promising blood-based biomarkers for HPV-associated cancers to date. Comparative validity analyses are warranted. Variations in tumor type-specific, high-risk HPV DNA prevalence according to anatomic site and world region highlight the need for biomarkers targeting more high-risk HPV types. Further investigation of blood-based microRNA expression profiling appears indicated.

Evaluating the Utility and Prevalence of HPV Biomarkers in Oral Rinses and Serology for HPV-related Oropharyngeal Cancer

Performance of commercially available human papillomavirus (HPV) assays (approved for cervical HPV detection) is unknown for detecting HPV-related oropharyngeal cancer (HPV-OPC). Assays for detection of HPV DNA [ELISA (DEIA) and Cobas], and RNA (Aptima) in oral rinse samples, and serum HPV oncogene antibodies were evaluated. Sensitivity and specificity of each test was explored among HPV-OPC cases and controls. Biomarker prevalence was evaluated among 294 "at-risk" people (screening) and 133 "high-risk" people [known to previously have oral oncogenic HPV (oncHPV) DNA and/or HPV16 E6/E7 antibodies detected]. HPV16 E6 antibodies had the best overall test performance with sensitivity of 88%, compared with oral HPV16 DNA sensitivity of 51% by DEIA and 43% by Cobas (each P < 0.001). Specificity was comparable in each of these tests (≥98%). When positivity for any oncHPV type was compared with HPV16 for the same test, sensitivity was comparable (60% vs. 51%, 40% vs. 43%, and 92% vs. 88% for DEIA, Cobas, and E6 antibodies, respectively), but specificity was reduced (93%-97%). Aptima had poor sensitivity (23%). Sensitivity decreased when cotesting HPV16 oral rinse DNA and E6 antibodies (37%-48%), or multiple E antibodies (69%-72%). HPV16 DNA were detected in ∼2% of the at-risk by either DEIA or Cobas and up to 15% of the high-risk population. HPV16 E6 seroprevalence was 2.3% and 2.4% in the at-risk and high-risk populations, respectively. Oral rinse HPV testing had moderate-to-poor sensitivity for HPV-OPC, suggesting many true positives would be missed in a potential screening scenario. HPV16 E6 serum antibody was the most promising biomarker evaluated.

Head and neck cancer prevention: from primary prevention to impact of clinicians on reducing burden

Survival from head and neck cancers (HNCs) of the lip, oral cavity, pharynx, and larynx has increased by 10% over the past few decades. Little over half of patients who develop HNCs will survive beyond 5 years. Survival is lower for individuals in many countries where traditional risk factors such as tobacco smoking, alcohol drinking, and betel quid chewing are highly prevalent but tertiary health care center access is limited or unavailable. Early diagnosis of HNC is the most important prognostic factor for each tumor site. Molecular-based research on HNC tumors holds promise for early stage detection, screening, vaccination, disease follow-up, and progression. Future investments for HNC control must consider both effectiveness and sustainability for both high- and low-resource countries alike, with priority toward risk factor prevention and earlier diagnosis.

Patients with early-stage oropharyngeal cancer can be identified with label-free serum proteomics

Background

The increasing incidence of oropharyngeal squamous cell carcinoma (OPSCC) is mainly related to human papillomavirus (HPV) infection. As OPSCCs are often diagnosed at an advanced stage, mortality and morbidity remain high. There are no diagnostic biomarkers for early detection of OPSCC.

Methods

Serum from 25 patients with stage I–II OPSCC, and 12 healthy controls, was studied with quantitative label-free proteomics using ultra-definition MS^E. Statistical analyses were performed to identify the proteins most reliably distinguishing early-stage OPSCCs from controls. P16 was used as a surrogate marker for HPV. P16-positive and P16-negative tumours were analysed separately.

Results

With two or more unique proteins per identification, 176 proteins were quantified. A clear separation between patients with early-stage tumours and controls was seen in principal component analysis. Latent structures discriminant analysis identified 96 proteins, most reliably differentiating OPSCC patients from controls, with 13 upregulated and 83 downregulated proteins in study cases. The set of proteins was studied further with network, pathway and protein–protein interaction analyses, and found to participate in lipid metabolism, for example.

Conclusions

We found a set of serum proteins distinguishing early-stage OPSCC from healthy individuals, and suggest a protein set for further evaluation as a diagnostic biomarker panel for OPSCC.

Screening for human papillomavirus-driven oropharyngeal cancer: Considerations for feasibility and strategies for research

The incidence and burden of human papillomavirus (HPV)‐driven oropharyngeal cancer is expected to increase for decades, thus motivating discussions regarding possibilities for screening. This article addresses issues related to the validity and timeliness of screening for HPV‐driven oropharyngeal cancer, and raises important questions, highlights deficits and confusion in the existing literature, and proposes needed steps in the research agenda.