HPV-associated oropharyngeal cancer: epidemiology, molecular biology and clinical management.

Human papillomavirus (HPV)-positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) has one of the most rapidly increasing incidences of any cancer in high-income countries. The most recent (8th) edition of the UICC/AJCC staging system separates HPV+ OPSCC from its HPV-negative (HPV-) counterpart to account for the improved prognosis seen in the former. Indeed, owing to its improved prognosis and greater prevalence in younger individuals, numerous ongoing trials are examining the potential for treatment de-intensification as a means to improve quality of life while maintaining acceptable survival outcomes. In addition, owing to the distinct biology of HPV+ OPSCCs, targeted therapies and immunotherapies have become an area of particular interest. Importantly, OPSCC is often detected at an advanced stage owing to a lack of symptoms in the early stages; therefore, a need exists to identify and validate possible diagnostic biomarkers to aid in earlier detection. In this Review, we provide a summary of the epidemiology, molecular biology and clinical management of HPV+ OPSCC in an effort to highlight important advances in the field. Ultimately, a need exists for improved understanding of the molecular basis and clinical course of this disease to guide efforts towards early detection and precision care, and to improve patient outcomes.

Investigating the effect of sexual behaviour on oropharyngeal cancer risk: a methodological assessment of Mendelian randomization.

BACKGROUND: Human papilloma virus infection is known to influence oropharyngeal cancer (OPC) risk, likely via sexual transmission. However, sexual behaviour has been correlated with other risk factors including smoking and alcohol, meaning independent effects are difficult to establish. We aimed to evaluate the causal effect of sexual behaviour on the risk of OPC using Mendelian randomization (MR). METHODS: Genetic variants robustly associated with age at first sex (AFS) and the number of sexual partners (NSP) were used to perform both univariable and multivariable MR analyses with summary data on 2641 OPC cases and 6585 controls, obtained from the largest available genome-wide association studies (GWAS). Given the potential for genetic pleiotropy, we performed a number of sensitivity analyses: (i) MR methods to account for horizontal pleiotropy, (ii) MR of sexual behaviours on positive (cervical cancer and seropositivity for Chlamydia trachomatis) and negative control outcomes (lung and oral cancer), (iii) Causal Analysis Using Summary Effect estimates (CAUSE), to account for correlated and uncorrelated horizontal pleiotropic effects, (iv) multivariable MR analysis to account for the effects of smoking, alcohol, risk tolerance and educational attainment. RESULTS: In univariable MR, we found evidence supportive of an effect of both later AFS (IVW OR = 0.4, 95%CI (0.3, 0.7), per standard deviation (SD), p = < 0.001) and increasing NSP (IVW OR = 2.2, 95%CI (1.3, 3.8) per SD, p = < 0.001) on OPC risk. These effects were largely robust to sensitivity analyses accounting for horizontal pleiotropy. However, negative control analysis suggested potential violation of the core MR assumptions and subsequent CAUSE analysis implicated pleiotropy of the genetic instruments used to proxy sexual behaviours. Finally, there was some attenuation of the univariable MR results in the multivariable models (AFS IVW OR = 0.7, 95%CI (0.4, 1.2), p = 0.21; NSP IVW OR = 0.9, 95%CI (0.5 1.7), p = 0.76). CONCLUSIONS: Despite using genetic variants strongly related sexual behaviour traits in large-scale GWAS, we found evidence for correlated pleiotropy. This emphasizes a need for multivariable approaches and the triangulation of evidence when performing MR of complex behavioural traits.

Comparison of HPV prevalence in HNSCC patients with regard to regional and socioeconomic factors.

HPV infection is considered as an independent risk factor for head and neck squamous cell carcinomas (HNSCC). Due to highly variable prevalence results in numerous studies, it is, however, difficult to estimate the relevance of HPV infection as risk factor for a specific patient collective. This study aimed to elucidate the disparities of HPV prevalence by analyzing socioeconomically and regionally different patient collectives. Two age, gender, stage and tumor location matched cohorts of 18 private health insured (PHIP) and 16 statutory health insured patients (SIP) suffering from an oropharyngeal squamous cell carcinoma (OSCC) and treated at a university hospital were screened for p16 overexpression and HPV infection by immunohistochemistry and PCR. In addition 85 HNSCC patients of an otolaryngology private practice (PPP) in a rural area were screened for p16 overexpression and positive cases were tested for HPV infection. HPV prevalence was 72.2% in the PHIP collective in comparison to 25.0% (p = 0.015) in the SIP collective with a significantly improved 5-year overall survival (p = 0.003) of the PHIP collective. The total HPV prevalence of PPP group was 7.1% with the highest infection rate in tonsillar carcinomas (33.3%) and a larger percentage of female patients in the HPV positive group (p = 0.037). This study shows that variable HPV infection rates in HNSCC can be caused by the selection of particular patient collectives, which suggest taking socioeconomic and regional factors into account for a decision on HPV testing, if it is not performed on a routine basis.

Use of tissue microarray to facilitate oncology research.

HPV-positive oropharyngeal squamous cell carcinomas (OSCC) represent a distinct disease entity from traditional OSCC. We hypothesized that for HPV DNA-positive cases, p16 expression status differentiates the biologically relevant ones.We determined HPV16DNA viral load in a cohort of 79 oropharyngeal squamous cell cancers by real-time polymerase chain reaction (PCR). We used cervical cancer as a disease model for HPV-initiated epithelial cancer. In cervical cancer, p53 and Rb expression is reduced, while p16 expression is increased. We used TMA technology to facilitate interrogation of this cohort for p53, Rb, and p16 protein expression using a quantitative, in situ method of protein analysis (AQUA analysis). Our results indeed delineate three biologically and clinically distinct types of oropharyngeal squamous cell cancers based on HPV-DNA determination and p16 expression status: one class of HPV-negative/p16-nonexpressing (HPV-negative), one class of HPV-positive/p16-nonexpressing (HPV-inactive), and one class of HPV positive/p16-expressing (HPV-active) oropharyngeal tumors. We demonstrated that only the HPV-active tumors share a similar molecular phenotype to cervical cancers, and are the ones associated with favorable prognosis.

Cyclin D1, glutathione S-transferase, and cytochrome P450 genotypes and outcome in patients with upper aerodigestive tract cancers: assessment of the importance of individual genes using multivariate analysis.

GST, CYP, and CCND1 genotypes have been associated with outcome in several cancers. Accordingly, we have examined, in patients with one squamous cell carcinoma (SCC) of the head and neck, associations between GSTM1, GSTT1, GSTM3, GSTP1, CYP2D6, CYP1A1, CYP2E1, and CCND1 genotypes and the outcome parameters, tumor extension, histological grade, and presence of nodes. We used logistic regression to study, first, each gene individually and, second, in a step-wise model that included all of the genes. Different genes were associated with each outcome parameter. Thus, GSTT1 null was associated with T3/T4 lesions in the oral cavity/pharyngeal (P = 0.029), but not laryngeal, SCC cases. GSTT1 null was also associated with histological differentiation (G3) in the oral cavity/pharyngeal, but not laryngeal, SCC cases, although this association only approached significance (P = 0.069). CCND1 GG was associated with G3 tumors in the oral cavity/pharyngeal (P = 0.011), but not laryngeal, SCC cases. The combination of GSTT1 null/CCND1 GG was also associated with G3 tumors. CYP2D6 PM and HET were associated with lymph node involvement in the laryngeal, but not oral/pharynx, SCC cases. Genes that were individually associated with outcome were also associated with the parameter in the step-wise routine. The GSTT1 null frequency was greater in 39 patients with second primary tumors than in those with one lesion (P = 0.014). The data demonstrate site-dependent associations between GSTT1 null, CCND1 GG, and CYP2D6 PM and tumor extension, differentiation, and nodes.