Cytokeratin 7 in Oropharyngeal Squamous Cell Carcinoma: A Junctional Biomarker for Human Papillomavirus-Related Tumors

Two Head and Neck Carcinomas With Squamous and Mucinous Components and Human Papillomavirus Associations: Maxillary Mucoepidermoid Carcinoma ex Sinonasal Schneiderian Papilloma and Tonsillar Invasive Stratified Mucin Producing Carcinoma (ISMC)

Carcinomas of the head-and-neck region with squamous and glandular/mucinous features constitute a heterogeneous group, with a significant minority of tumors showing an human papillomavirus (HPV) association. The differential diagnosis is usually between mucoepidermoid carcinoma (MEC) and adenosquamous carcinoma. We present here two tumors that exemplify both the challenges of diagnostic classification, as well as the complex relationship to HPV: (a) a low risk HPV positive/p16 negative carcinoma that is most consistent with a relatively typical intermediate grade mucoepidermoid type carcinoma with complete MEC phenotype (three cell types), originating from intranasal sinonasal papillomas with exophytic and inverted patterns, and invading surrounding maxillary compartments, and (b) a p16 and keratin 7 (KRT7) positive carcinoma of the right tonsil, characterized by stratified squamous and mucinous cell (mucocyte) features. Whereas the first tumor represents a typical MEC ex-Schneiderian papilloma, the second is morphologically most consistent with the, novel for this anatomic location, diagnosis of "invasive stratified mucin producing carcinoma" (ISMC), pointing to an analogy to similar, high-risk HPV-driven malignancies recently described in the gynecologic (GYN) and genitourinary (GU) areas. Both tumors, despite their mucoepidermoid-like features had no connection to salivary glands and lacked the MAML2 translocation typical of salivary gland MEC, pointing to a mucosal/non-salivary gland origin. Using these two carcinomas as examples, we attempt to address questions related to: (a) the histological distinction between MEC, adenosquamous carcinoma, and ISMC, (b) similarities and differences between these histological entities in mucosal sites versus morphologically similar salivary gland tumors, and (c) the role of HPV in these tumors.

Analysis of cells of epithelial, connective tissue and immune differentiation in HPV-positive-, HPV-negative oropharyngeal carcinoma and normal oropharyngeal tissue by immunofluorescence multiplex image cytometry: a preliminary report

BACKGROUND

Epithelial, connective tissue and immune cells contribute in various ways to the pathophysiology of HPV positive (HPV+) and HPV negative (HPV-) oropharyngeal squamous cell carcinoma (OPSCC). We aimed to investigate the abundance of these cell lineages and their coexpression patterns in patients with HPV + and HPV- OPSCC.

METHODS

We used a 4-channel immunofluorescence-microscopy technique for the simultaneous detection of three direct-conjugated antibodies (pancytokeratin, vimentin and CD45/CD18) and DAPI (4',6-Diamidin-2-phenylindole) in formalin fixed paraffin-embedded tissue samples (FFPE) of patients with HPV + and HPV- OPSCC, and of control patients. Image acquisition and analysis were performed with TissueFAXS and StrataQuest (TissueGnostics, Vienna, Austria), respectively, in tumor cell clusters/stroma in OPSCC specimens and epithelial layer/lamina propria in control specimens. Cell populations were created based on antibodies' coexpression patterns. Isotype and positive controls were examined for plausibility.

RESULTS

The proportion of cells of epithelial differentiation in tumor cell clusters was higher in HPV + OPSCC (55%) than in HPV- OPSCC samples (44%). The proportion of connective tissue cells in tumor cell cluster was lower in HPV + OPSCC patients (18%) than in HPV- OPSCC patients (26%). The proportion of immune cells in tumor cell clusters was higher in HPV + OPSCC patients (25%) than in HPV- OPSCC patients (18%). The percentage of anaplastic, potentially de-differentiated cells, was 2% in control patients, and it was higher in HPV- OPSCC (21%) than in HPV + OPSCC samples (6%).

CONCLUSIONS

This study provided the first quantitative data for the abundance of cells of epithelial, connective tissue and immune differentiation, in patients with OPSCC and control patients. The abundance of these different crucial cell populations was consistently originating from the same tissue sample. De-differentiation of tumor cells was higher in HPV- OPSCC than in HPV + OPSCC. In tumor cells clusters, the antitumoral host immune response was higher in HPV + OPSCC than in HPV- OPSCC, whereas the fibroblast response was higher in HPV- OPSCC than in HPV + OPSCC. This study contributed to the understanding of histopathologic differences between HPV + OPSCC and HPV- OPSCC patients.

Squamous–columnar junction of Von Ebner’s glands may be a significant origin of squamous cell carcinomas in the base of the tongue

Objectives

The histological origin of base of the tongue (BOT) carcinomas is still elusive, and most studies have been focusing on the lingual tonsil. In this study, we sought to identify the existence of the squamous–columnar junction (SCJ) in the human Von Ebner’s glandular duct and explored the potential of that in forming squamous cell carcinomas in BOT.

Materials and methods

The specific genomes of BOT carcinoma were acquired and screened out by The Cancer Genome Atlas (TCGA) database analysis. The 4-nitroquinoline-1-oxide (4-NQO)-treated mouse model was used to explore the transformation of SCJ during cancerization. We used immunohistochemistry to confirm the characteristics of SCJ in human Von Ebner’s gland, which were further compared with those in the anus and cervix.

Results

The SCJ in the human Von Ebner’s glandular duct was found to be similar to that of the cervix and anus. The transformation zone in the 4-NQO-treated mouse model had a multilayered epithelium structure similar to that of HPV16-transgenic mice. In human, the transformation zone of Von Ebner’s gland is also similar to that of the cervix and anus.

Conclusion

It is the first time that the existence of SCJ in the opening of the human Von Ebner’s glandular duct was confirmed. The SCJ of Von Ebner’s glands may be a significant origin of squamous cell carcinomas in BOT.

Generation of human tonsil epithelial organoids as an ex vivo model for SARS-CoV-2 infection

The palatine tonsils (hereinafter referred to as "tonsils") serve as a reservoir for viral infections and play roles in the immune system's first line of defense. The aims of this study were to establish tonsil epithelial cell-derived organoids and examine their feasibility as an ex vivo model for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The tonsil organoids successfully recapitulated the key characteristics of the tonsil epithelium, including cellular composition, histologic properties, and biomarker distribution. Notably, the basal layer cells of the organoids express molecules essential for SARS-CoV-2 entry, such as angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin, being susceptible to the viral infection. Changes in the gene expression profile in tonsil organoids revealed that 395 genes associated with oncostatin M signaling and lipid metabolism were highly upregulated within 72 h after SARS-CoV-2 infection. Notably, remdesivir suppressed the viral RNA copy number in organoid culture supernatants and intracellular viral protein levels in a dose-dependent manner. Here, we suggest that tonsil epithelial organoids could provide a preclinical and translational research platform for investigating SARS-CoV-2 infectivity and transmissibility or for evaluating antiviral candidates.

Survival-related epithelial-mesenchymal transition proteins in oropharyngeal squamous cell carcinoma: A systematic review and meta-analysis

OBJECTIVE

To aim of this systematic review was to explore the relationship between Human papillomavirus (HPV) and epithelial-mesenchymal transition (EMT) related to the prognosis of oropharyngeal squamous cell carcinoma (OPSCC).

DESIGN

For this systematic review, searches were performed in PubMed, Web of Science, Scopus, Science Direct, and Cochrane, and a random-effects model was used for meta-analysis. The presence of EMT was confirmed by the loss of E-cadherin immunoexpression and overexpression of vimentin.

RESULTS

In summary, EMT-related proteins were expressed regardless of HPV status; however, overall survival was better in HPV-positive OPSCC cases, with a 5.88 times lower death risk compared to HPV-negative patients (OR=0.17; 95%CI=0.10-0.30). Likewise, the maintenance of E-cadherin in OPSCC was associated with an 11.11 times lower risk of death due to the disease (OR=0.09; 95%CI=0.01-0.88).

CONCLUSIONS

More advanced clinical stages (III/IV) and the presence of lymph node metastases (N1-3) were common in OPSCC but were not significantly associated with HPV status.

A Novel Model for Papillomavirus-Mediated Anal Disease and Cancer Using the Mouse Papillomavirus

Up to 95% of all anal cancers are associated with infection by human papillomavirus (HPV); however, no established preclinical model exists for high-grade anal disease and cancer mediated by a natural papillomavirus infection. To establish an infection-mediated model, we infected both immunocompromised NSG and immunocompetent FVB/NJ mice with the recently discovered murine papillomavirus MmuPV1, with and without the additional cofactors of UV B radiation (UVB) and/or the chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). Infections were tracked via lavages and swabs for MmuPV1 DNA, and pathology was assessed at the endpoint. Tissues were analyzed for biomarkers of viral infection and papillomavirus-mediated disease, and the localization of viral infection was investigated using biomarkers to characterize the anal microanatomical zones.

Cytokeratin 7 and 19 expression in oropharyngeal and oral squamous cell carcinoma

PURPOSE

The precise etiopathogenesis of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC), and reasons for predilection for crypt epithelium, remain uncertain. The purpose of this study is to investigate the interaction between HPV and specific cytokeratins 7 (CK7) and 19 (CK19) in crypt epithelium.

METHODS

This is a retrospective cohort study of patients presenting between 1999 and 2015 at a tertiary referral center. CK7 and CK19 positivity and H Scores were determined by immunohistochemistry. Disease-specific and overall survival rates were analyzed.

RESULTS

There were 253 patients presenting with OPSCC (134), squamous cell carcinoma (SCC) of unknown primary site (22), and oral tongue SCC (97). Primary tumor CK7 and CK19 positivity and H Scores were significantly higher in HPV-positive OPSCC than HPV-negative OPSCC and oral tongue SCC. Higher CK19 Scores, but not CK7 Scores, were also seen in regional metastases from HPV-positive OPSCC than other sites. No impact on disease-specific or overall survival was identified on multivariate analysis.

CONCLUSION

The increased expression of CK7 and CK19 in HPV-positive OPSCC compared to HPV-negative disease supports the theory for a role for these cytokeratins in the etiopathogenesis of HPV-related OPSCC.

N6 -Methyladenosine Regulates mRNA Stability and Translation Efficiency of KRT7 to Promote Breast Cancer Lung Metastasis

The roles of RNA modification during organ metastasis of cancer cells are not known. Here we established breast cancer lung metastasis cells by three rounds of selection of lung metastatic subpopulations in vivo and designated them as BC^LMF3 cells. In these cells, mRNA N⁶ -methyladenosine (m⁶A) and methyltransferase METTL3 were increased, while the demethylase FTO was decreased. Epi-transcriptome and transcriptome analyses together with functional studies identified keratin 7 (KRT7) as a key effector for m⁶A-induced breast cancer lung metastasis. Specifically, increased METTL3 methylated KRT7-AS at A877 to increase the stability of a KRT7-AS/KRT7 mRNA duplex via IGF2BP1/HuR complexes. Furthermore, YTHDF1/eEF-1 was involved in FTO-regulated translational elongation of KRT7 mRNA, with methylated A950 in KRT7 exon 6 as the key site for methylation. In vivo and clinical studies confirmed the essential roles of KRT7, KRT7-AS, and METTL3 for lung metastasis and clinical progression of breast cancer. Collectively, m⁶A promotes breast cancer lung metastasis by increasing the stability of a KRT7-AS/KRT7 mRNA duplex and translation of KRT7. SIGNIFICANCE: This study suggests that N⁶ -methyladenosine is a key driver and potential therapeutic target in breast cancer metastasis.

The unveiled reality of human papillomavirus as risk factor for oral cavity squamous cell carcinoma

The prognostic impact of human papillomavirus (HPV) in oropharyngeal cancer is generally acknowledged, and HPV-status is assessed routinely in clinical practice. Paradoxically, while the oral cavity seems the predilection site for productive HPV-infections, figures on HPV-attribution in oral cavity squamous cell carcinoma (OCSCC) differ widely, and prognostic impact is uncertain. Major obstacles are the lack of reproducible assays to detect HPV in nonoropharyngeal cancers, the relatively small cohorts studied and consequently the shortfall of convincing data. In our study, we used a validated, nucleic acid-based workflow to assess HPV-prevalence in a consecutive cohort of 1016 OCSCCs, and investigated its prognostic impact. In parallel, we analyzed p16-immunohistochemistry (p16-IHC) as surrogate marker for transforming HPV-infection and independent prognosticator. All OCSCC-patients diagnosed between 2008 and 2014 at two Dutch university medical centers were included (N = 1069). Formalin-fixed, paraffin-embedded (FFPE)-samples of 1016 OCSCCs could be retrieved. Punch biopsies were taken from the tumor area in the FFPE-blocks and tested for HPV. P16-IHC was performed on 580 OCSCCs, including all HPV-positive tumors. From 940 samples (92.5%), nucleic acids were of sufficient quality for HPV-testing. In total, 21 (2.2%) OCSCCs were HPV DNA-positive. All HPV DNA-positive tumors were E6 mRNA-positive and considered as true HPV-positive. There was no difference in survival between HPV-positive and HPV-negative OCSCCs. In total, 46 of 580 (7.9%) OCSCCs were p16-immunopositive, including all HPV-positive tumors. Survival was comparable in p16-positive and p16-negative OCSCCs. To conclude, HPV-prevalence is very low in OCSCC and neither HPV-status nor p16-status affects outcome. Based on these data, determining HPV-status in OCSCC seems irrelevant for clinical management.

EGFR overexpression increases radiotherapy response in HPV-positive head and neck cancer through inhibition of DNA damage repair and HPV E6 downregulation

High-risk Human Papillomavirus (HPV) infections have recently emerged as an independent risk factor in head and neck squamous cell carcinoma (HNSCC). There has been a marked increase in the incidence of HPV-induced HNSCC subtype, which demonstrates different genetics with better treatment outcome. Despite the favourable prognosis of HPV-HNSCC, the treatment modality, consisting of high dose radiotherapy (RT) in combination with chemotherapy (CT), remains similar to HPV-negative tumours, associated with toxic side effects. Epidermal growth factor receptor (EGFR) is overexpressed in over 80% of HNSCC and correlates with RT resistance. EGFR inhibitor Cetuximab is the only FDA approved targeted therapy for both HNSCC subtypes, however the response varies between HNSCC subtypes. In HPV-negative HNSCC, Cetuximab sensitises HNSCC to RT improving survival rates. To reduce adverse cytotoxicity of CT, Cetuximab has been approved for treatment de-escalation of HPV-positive HNSCC. The results of several recent clinical trials have concluded differing outcome to HPV-negative HNSCC. Here we investigated the role of EGFR in HPV-positive HNSCC response to RT. Remarkably, in HPV-positive HNSCC cell lines and in vivo tumour models, EGFR activation was strongly indicative of increased RT response. In response to RT, EGFR activation induced impairment of DNA damage repair and increased RT response. Furthermore, EGFR was found to downregulate HPV oncoproteinE6 expression and induced p53 activity in response to RT. Collectively, our data uncovers a novel role for EGFR in virally induced HNSCC and highlights the importance of using EGFR-targeted therapies in the context of the genetic makeup of cancer.

The role of tumour morphology in assigning HPV status in oropharyngeal squamous cell carcinoma

OBJECTIVES

There is no consensus on the optimal approach to human papilloma virus (HPV) testing in oropharyngeal squamous cell carcinoma (OPSCC). Our objective was to classify OPSCC as HPV positive or negative based on (1) morphology alone, (2) p16 status alone, (3) combined morphology and p16 status with additional HPV testing in discordant cases in keeping with 2012 College of American Pathologists (CAP) guidelines (combined approach), and to evaluate and compare survival outcomes.

MATERIALS AND METHODS

Retrospective review of 168 patients, 146 with OPSCC and 22 with cervical SCC of unknown primary site (SCCUP). Morphology was classified as keratinizing or non-keratinizing, p16 immunohistochemistry (IHC) performed and additional HPV DNA PCR testing undertaken in cases in which morphology and p16 status were discordant. Survival statistics were evaluated and compared for the 3 different approaches to classification.

RESULTS

On univariate analysis all 3 classification methods significantly predicted for overall survival (OS). Both p16 status and the combined approach also predicted for disease specific survival (DSS), whereas morphology fell just outside significance (p = 0.06). On multivariate analysis only the combined approach retained significance for both OS and DSS, whilst morphology was also significant for DSS.

CONCLUSIONS

Our findings confirm that tumour morphology significantly predicts for survival in OPSCC. However, we found combined tumour morphology and p16 IHC, with additional testing for discordant cases to be superior to either morphology or p16 IHC alone. Further study is required to establish the optimal testing method for HPV in OPSCC particularly in low prevalence populations.

Modelling human papillomavirus biology in oropharyngeal keratinocytes

Most human papillomavirus (HPV) positive head and neck cancers arise in the tonsil crypts; deep invaginations at the tonsil surface that are lined with reticulated epithelium infiltrated by immune cells. As in cervical HPV infections, HPV16 is the most prevalent high-risk type in the oropharyngeal cancers, and a genital-oral route of infection is most likely. However, the natural history of HPV-driven oropharyngeal pathogenesis is an enigma, although there is evidence that it is different to that of cervical disease. It is not known if the virus establishes a productive or abortive infection in keratinocytes of the tonsil crypt, or if viral infections progress to cancer via a neoplastic phase, as in cervical HPV infection. The HPV DNA is more frequently found unintegrated in the cancers of the oropharynx compared to those that arise in the cervix, and may include novel HPV-human DNA hybrids episomes. Here, we review current understanding of HPV biology in the oropharynx and discuss the cell-based systems being used to model the HPV life cycle in tonsil keratinocytes and how they can be used to inform on HPV-driven neoplastic progression in the oropharynx.

This article is part of the theme issue ‘Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses’.

HPV16 is sufficient to induce squamous cell carcinoma specifically in the tongue base in transgenic mice

Head and neck squamous cell carcinomas (HNSCCs) associated with human papillomavirus (HPV) occur specifically in the tonsils and the tongue base, but the reasons for this specificity remain unknown. We studied the distribution of oral and pharyngeal lesions in HPV16-transgenic mice where the expression of all the HPV16 early genes is targeted to keratinising squamous epithelia by the cytokeratin 14 (Krt14) gene promoter. At 30 weeks of age, 100% of mice developed low- and high-grade intraepithelial dysplasia at multiple sites. Twenty per cent of animals developed invasive cancers that remarkably were restricted to the tongue base, in association with the circumvallate papilla. The lesions maintained expression of CK14 (KRT14) and the HPV16 E6 and E7 oncogenes, and displayed deregulated cell proliferation and up-regulation of p16^INK4A . Malignant lesions were poorly differentiated and destroyed the tongue musculature. We hypothesised that the tongue base area might contain a transformation zone similar to those observed in the cervix and anus, explaining why HPV-positive cancers target that area specifically. Immunohistochemistry for two transformation zone markers, CK7 (KRT7) and p63 (TP63), revealed a squamocolumnar junction in the terminal duct of von Ebner's gland, composed of CK7⁺ luminal cells and p63⁺ basal cells. Dysplastic and invasive lesions retained diffuse p63 expression but only scattered positivity for CK7. Site-specific HPV-induced carcinogenesis in the tongue base may be explained by the presence of a transformation zone in the circumvallate papilla. This mouse model reproduces key morphological and molecular features of HPV-positive HNSCC, providing a unique in vivo tool for basic and translational research. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Decreased cytokeratin 7 expression correlates with the progression of cervical squamous cell carcinoma and poor patient outcomes

AIM

To identify potential biomarkers for tumor progression and patient outcomes in cervical squamous cell carcinoma.

METHODS

We examined the expressions of CK7 and CK17 as potential markers of the squamo-columnar junction, and podoplanin as a basal cell marker using surgical and biopsy samples of patients in grade 3 cervical intraepithelial neoplasia (n = 30), operable invasive carcinoma (OP group, n = 53) and inoperable invasive carcinoma before radiotherapy and/or chemotherapy (RC group, n = 76).

RESULTS

The positive rates of CK7 and podoplanin in invasive carcinoma were significantly lower than those in grade 3 cervical intraepithelial neoplasia (P = 0.001, P < 0.0001). The positive rates of CK7 and podoplanin in the RC group were significantly lower than those in the OP group (P < 0.0001, P = 0.04), while CK17 expression showed significantly higher positivity in the RC group than in the OP group (P < 0.0001). Negative CK7 expression showed a potential impact on overall survival in early-stage patients. In the RC group, the prevalence of cases with post-therapeutic residual carcinoma cells was higher in the CK7-negative group than in the positive group (P = 0.003). We found that decreased expression of CK7 could be a prognostic factor in early-stage cervical cancer patients.

CONCLUSION

This result may provide strategies and suggestions for new treatment options and follow-up practices in managing patients with cervical cancer.

The prognostic effect of anatomic subsite in HPV-positive oropharyngeal squamous cell carcinoma

BACKGROUND

Since most HPV-associated disease occurs in the tonsillar-related areas (TRA) - palatine and lingual tonsils, the effect of HPV on survival in non-tonsillar oropharyngeal subsites (nTRA) is not well established. The objective of this study was to use a large population-based cohort to investigate the survival impact of HPV in nTRA subsites versus TRA subsites.

METHODS

This SEER database study was conducted by stratifying the HPV-positive oropharyngeal cancer cohort into two primary groups, TRA and nTRA.

RESULTS

HPV-positive squamous cell cancer was significantly more common in TRAs (73%) compared to nTRAs (31.2%, p < 0.001). After controlling for age, treatment, stage, race, and income, patients with HPV-positive disease in nTRAs had a worse cause-specific survival (CSS) than individuals with HPV-positive disease in TRAs (HR = 2.16, 95% CI 1.20-3.86, p = 0.01).

CONCLUSION

Patients with HPV-positive OPSCC in nTRAs had poorer survival outcomes compared to patients with HPV-positive OPSCC in TRAs.

Outcomes of transoral laser microsurgery for oropharyngeal squamous cell carcinoma in Ireland and review of the literature on transoral approaches

BACKGROUND

The optimal treatment for oropharyngeal squamous cell carcinoma (OPSCC) is controversial. There is increasing evidence that, in selected cases, minimally invasive transoral surgery can offer improved functional outcomes, with equivalent oncologic outcomes, compared to chemoradiotherapy.

AIMS

We report the outcomes of transoral laser microsurgery (TLM) for treatment of OPSCC at our institution.

METHODS

Patients with OPSCC undergoing TLM at the South Infirmary Victoria University Hospital, Cork, between 2010 and 2016, were identified from an institutional database. Human papillomavirus (HPV) status was determined by p16 immunohistochemistry. Survival outcomes were analysed using the Kaplan-Meier method. Complications following surgery and gastrostomy tube dependence were evaluated.

RESULTS

The study cohort consisted of 26 patients, with mean age of 56 years (range 29-71). Primary tumours were located in the tonsil (18), base of tongue (4) and other subsites (4). Seventeen cases were p16-positive. Complications included haemorrhage necessitating return to theatre (1) and aspiration pneumonia (1). Four patients underwent tracheostomy, all of whom were successfully decannulated. One patient underwent gastrostomy tube insertion during postoperative radiotherapy. No patient was gastrostomy dependent at latest follow-up. Twenty-two patients received adjuvant treatment, with radiation alone (21) or chemoradiotherapy (2). Mean follow-up was 27 months. Five-year locoregional control was 92% and disease-specific survival was 81%.

CONCLUSIONS

In selected patients with OPSCC, TLM offers excellent functional and survival outcomes, and as such offers an alternative approach to chemoradiotherapy as primary treatment. We compare TLM to other transoral approaches and discuss its potential use in the Irish healthcare system.

The molecular landscape of head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are unexpectedly heterogeneous in nature. Classical risk factors are smoking and excessive alcohol consumption, and in recent years, the role of human papillomavirus (HPV) has emerged, particularly in oropharyngeal tumours. HPV-induced oropharyngeal tumours are considered a separate disease entity, which recently has manifested in an adapted prognostic staging system while the results of de-intensified treatment trials are awaited. Carcinogenesis caused by HPV in the mucosal linings of the upper aerodigestive tract remains an enigma, but with some recent observations, a model can be proposed. In 2015, The Cancer Genome Atlas (TCGA) consortium published a comprehensive molecular catalogue on HNSCC. Frequent mutations of novel druggable oncogenes were not demonstrated, but the existence of a subgroup of genetically distinct HPV-negative head and neck tumours with favourable prognoses was confirmed. Tumours can be further subclassified based on genomic profiling. However, the amount of molecular data is currently overwhelming and requires detailed biological interpretation. It also became apparent that HNSCC is a disease characterized by frequent mutations that create neoantigens, indicating that immunotherapies might be effective. In 2016, the first results of immunotherapy trials with immune checkpoint inhibitors were published, and these may be considered as a paradigm shift in head and neck oncology.

Expression and Significance of Cytokeratin 7, a Squamocolumnar Junction Marker, in Head and Neck Squamous Cell Carcinoma

The favorable features of high-risk human papillomavirus (HPV) in the head and neck are limited to those harboring transcriptionally-active HPV, which occur predominantly in the oropharynx (OP). Factors rendering the OP susceptible to HPV oncogenesis are largely unexplored. The role of cytokeratin 7 (CK7) in predisposition to HPV and cancer in the cervix has been evaluated. However, its significance in the H&N is unknown. CK7 immunohistochemistry was performed on a tissue microarray cohort of OP and non-oropharyngeal (NOP) squamous cell carcinomas (SCC) with known clinical follow-up and HPV E6/7 mRNA status. Expression was graded based on the distribution (1 ≤ 33%, 2 = 33-66%, 3 ≥ 66%) and intensity (1 = weak, 2 = strong) with combined score of ≥ 2 considered positive. Survival analysis was performed. Seventy-four NOPSCCs and 204 OPSCCs were studied. HPV was positive in 2.7% of NOPSCCs and 70.9% of OPSCCs. CK7 was positive in 23.0% of OPSCCs and 14.8% of NOPSCCs (p = 0.2), and in 24.1% of HPV positive versus 17.2% of negative patients (p = 0.2). There was no correlation with age, race, gender, HPV status, histologic type, tumor subsite, treatment, stage, or co-morbidities, and CK7 expression was not significantly associated with overall or disease specific survival. In our series, CK7 is positive in ~ 25% of H&N SCCs, although usually only focally. While CK7 has been suspected to be overexpressed selectively in HPV-related OPSCCs due to their origination from tonsillar crypt epithelium, we did not find any significant difference by anatomic H&N subsite, nor by HPV status, for its expression and found no association with patient survival.

Cytokeratin7 expression in histologic and cytologic specimens of cystic neck metastasis from HPV positive squamous cell carcinoma of the tonsil: A case report

The majority of cystic squamous cell carcinomas (SCCs) of the neck have been shown to be metastatic tumors from tonsillar SCCs associated with high‐risk human papillomavirus (HR HPV). Recent studies have demonstrated cytokeratin (CK)7 involvement in the development of HPV positive SCC, but no report has been issued on its simultaneous expression in primary tonsillar and metastatic tumor with cystic change. We present a case of HPV positive tonsillar SCC of a 42‐year‐old male that initially manifested as a cystic neck mass expressing CK7, CK19, and p16 in primary and metastatic tumors. Immunohistochemical examination revealed diffuse CK19 and p16 expression, and patchy CK7 expression in the solid components of primary and metastatic tumors. However, in cystic components of metastatic tumors the expression of CK7 and CK19 was preserved but p16 expression was absent, which was consistent with immunocytochemical findings of fine‐needle aspirates from cystic neck mass. In immunocytochemistry performed on aspirates of a branchial cleft cyst for the comparison of cystic SCC and benign cyst, CK19 staining was positive but CK7 and p16 staining was negative. These results suggest that CK7 immunocytochemistry on aspirated material from cystic neck mass may be a useful adjunct for distinguishing cystic metastasis of tonsillar SCC from branchial cleft cyst, although a larger scale study would be required.