Human papillomavirus in oropharyngeal squamous cell carcinoma: assessing virus presence in normal tissue and activity in cervical metastasis

[Challenges and limits of therapeutic de-escalation for papillomavirus-related oropharyngeal cancer]

The incidence of HPV-related oropharyngeal cancers has been increasing in Western countries for several decades. If they are individualized within the latest TNM classification, the current standards of management do not authorize the management of these patients to be singled out. However, their distinct oncogenesis and their excellent prognosis compared to other patients has allowed the development of several clinical trials based on the question of therapeutic de-escalation. This review of the literature aims to take stock of the elements provided by clinical research in recent years.

Prevalence of Transcriptionally Active HPV Infection in Tumor-Free Oropharyngeal Tissue of OPSCC-Patients

Objectives

The natural history of HPV-related oropharyngeal squamous cell carcinoma (OPSCC) is still largely unknown. Since reports of second primary tumors (SPTs) in patients with HPV-related OPSCCs are increasing, a multifocal HPV infection, hinting a «virus-induced field effect», has been hypothesized. This study aimed to investigate the HPV-prevalence in normal appearing oropharyngeal tissue in patients with OPSCCs.

Materials and Methods

49 OPSCC patients undergoing panendoscopy were prospectively enrolled. Tumor specimens and biopsies of normal appearing oropharyngeal tissue adjacent to and distant from the index OPSCC underwent histopathological examination, p16INK4A immunohistochemical staining, HPV DNA and mRNA-detection. Patient characteristics and follow-up data on SPTs were obtained.

Results

26 of 49 (53%) OPSCC were positive for HPV DNA and p16INK4A. HPV mRNA was detected in 23 of 26 (88%) of these tumor samples. HPV DNA was detected in 36% adjacent mucosa and in 17% distant mucosa samples and only in patients with an HPV-related index OPSCC. HPV mRNA could not be detected in tumor-free distant and adjacent mucosa samples. No evidence of association between HPV detection in normal appearing mucosa and development of second primary tumors was found.

Conclusions

HPV was detectable but not transcriptionally active in adjacent/distant tumor-free oropharyngeal tissue. This suggests that a multifocal HPV infection, hinting a «virus-induced fielcd cancerization», may not be pertaining to HPV-related OPSCC.

Basaloid Squamous Cell Carcinoma of the Anus Revisited

Basaloid squamous cell carcinoma (SCC) of the anus, previously called cloacogenic carcinoma, is a subtype of SCC. There are very few data on the morphologic variation within basaloid SCC of the anus, which may contribute to misdiagnosis. We retrospectively evaluated cases originally diagnosed as basaloid SCC for histologic characterization. We retrieved and reviewed cases of basaloid SCC from 1994 to 2013. Ten (27%) cases were reclassified after review, including basal cell carcinoma (n=6), melanoma (n=2), and neuroendocrine carcinoma (n=2). The final group of basaloid SCC (n=27) showed a female predominance (median age=60 y; range, 42 to 92 y). Morphologically, basaloid SCC could be categorized into 4 groups: transitional carcinoma like (n=10), basaloid with peripheral palisade (n=13), adenoid cystic carcinoma like (n=3), and mucinous microcystic (n=1). In 19 cases the histologic patterns were pure and were mixed in the remainder. CK5/6, p16, and high-risk HPV were positive in all cases (n=27). SOX2 was positive in 18/22 cases. Clinical follow-up was available on 60% of cases; 9 patients (53%) developed local recurrence or metastasis, and 5 (29%) died of disease. Basaloid SCC of the anus is characterized by 4 major histologic patterns and is consistently HPV driven.

LMP1 Increases Expression of NADPH Oxidase (NOX) and Its Regulatory Subunit p22 in NP69 Nasopharyngeal Cells and Makes Them Sensitive to a Treatment by a NOX Inhibitor

Oxidative stress is thought to contribute to cancer development. Epstein–Barr virus (EBV) and its encoded oncoprotein, latent membrane protein 1 (LMP1), are closely associated with the transformation of nasopharyngeal carcinoma (NPC) and Burkitt’s lymphoma (BL). In this study, we used LMP1-transformed NP cells and EBV-related malignant cell lines to assess the effects of LMP1 on reactive oxygen species (ROS) accumulation and glycolytic activity. Using NPC tissue samples and a tissue array to address clinical implications, we report that LMP1 activates NAD(P)H oxidases to generate excessive amount of ROS in EBV-related malignant diseases. By evaluating NAD(P)H oxidase (NOX) subunit expression, we found that the expression of the NAD(P)H oxidase regulatory subunit p22^phox was significantly upregulated upon LMP1-induced transformation. Furthermore, this upregulation was mediated by the c-Jun N-terminal kinase (JNK) pathway. In addition, LMP1 markedly stimulated anaerobic glycolytic activity through the PI3K/Akt pathway. Additionally, in both NPC cells and tissue samples, p22^phox expression correlated with LMP1 expression. The NAD(P)H oxidase inhibitor diphenyleneiodonium (DPI) also exerted a marked cytotoxic effect in LMP1-transformed and malignant cells, providing a novel strategy for anticancer therapy.

The pathology of HPV-related head and neck cancer: implications for the diagnostic pathologist

A subset of head and neck squamous cell carcinomas are caused by the human papillomavirus (HPV). This HPV-related form of head and neck squamous cell carcinoma (HPV-HNSCC) has captured the attention of the oncology community for its rising incidence, its link to non-traditional risk factors, and its divergent clinical behavior. To diagnose this special form of head and neck squamous cell carcinoma is to provide important prognostic information and, in some instances, redirect clinical therapy. The diagnosis of HPV-HNSCC is aided by a strong appreciation for its characteristic microscopic findings and by an awareness of aberrant features that set apart a growing list of HPV-HNSCC morphologic variants. This review will delineate the microscopic appearance of HPV-HNSCC, spotlight ways in which the misinterpretation of these microscopic features can lead to diagnostic confusion, offer recommendations for appropriate terminology when diagnosing HPV-HNSCC, and provide examples of specific diagnostic scenarios where HPV testing can inform the diagnostic process.

Patients with HPV-related tonsil squamous cell carcinoma rarely harbour oncogenic HPV infection at other pharyngeal sites

OBJECTIVES

Patients with human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) have a reduced risk of developing second primary upper aerodigestive tract (UADT) tumours compared to patients with HPV-negative primary tumours at the same site. To determine whether this finding might be explained by a lack of viral-induced field cancerisation or multifocal infection, we investigated whether there was epithelial dysplasia and/or evidence of HPV infection at other pharyngeal mucosal sites in patients presenting with the disease.

MATERIALS AND METHODS

Sixty-three patients with primary tonsil SCC and 108 pharyngeal endoscopic biopsies, representing at least one pharyngeal subsite from each patient, were included in this study. Tissue samples were tested using HPV PCR (GP5+/6+), p16 immunohistochemistry (IHC) and high risk HPV DNA in situ hybridisation (ISH).

RESULTS

There were 46 patients with HPV-related SCC and 17 patients with HPV-negative disease. PCR detected HPV DNA in a fifth of pharyngeal endoscopic biopsies and was equally likely to be from a patient with HPV-related SCC as from a patient with HPV negative disease. All PCR positive cases were tested using p16 IHC and high risk HPV ISH and only three biopsies were positive. Significantly, these three biopsies all showed evidence of epithelial dysplasia and were from patients with an HPV positive index tumour.

CONCLUSION

Our data suggest that virus-induced field cancerisation and/or multifocal oncogenic HPV infection of the pharynx is uncommon in OPSCC and supports the concept that these patients have a lower risk of developing second primary tumours of the UADT.