Oropharyngeal squamous cell carcinoma: p16/p53 immunohistochemistry as a strong predictor of HPV tumour status

Human papillomavirus detection rates in Bowen disease: correlation with pelvic and digital region involvement and specific p53 immunostaining patterns

BACKGROUND

The relationship between human papillomavirus (HPV) and Bowen disease (BD) is not fully understood.

OBJECTIVES

To investigate the differences in HPV detection rates in BD samples across various body regions and analyse the expression patterns of p53, p16 and Ki-67 in relation to HPV presence.

METHODS

Tissue samples from patients diagnosed with BD, confirmed through histopathology, were retrospectively collected. Next-generation sequencing was used for HPV DNA detection. Immunohistochemistry (IHC) for p16, p53 and Ki-67 was performed.

RESULTS

Out of 109 patients with BD, 21 (19.3%) were HPV-positive. All identified types were α-HPVs, with HPV-16 being the most common. The HPV detection rate was significantly higher in the pelvic (9/13, 69%, P < 0.001) and digital (5/10, 50%, P = 0.02) areas compared with those in the other regions. HPV presence was significantly correlated with p53 negativity (P = 0.002), the p53 'non-overexpression' IHC pattern (P < 0.001) and p16-p53 immunostain pattern discordance (P < 0.001). Conversely, there was no notable association between HPV presence and p16 positivity, the p16 IHC pattern or Ki-67 expression.

CONCLUSIONS

Our findings suggest the oncogenic role of sexually transmitted and genito-digitally transmitted α-HPVs in the pathogenesis of BD in pelvic and digital regions.

GRAPHICAL ABSTRACT

Immunoreactivity of LMO7 and other molecular markers as potential prognostic factors in oropharyngeal squamous cell carcinoma

BACKGROUND

Despite the better prognosis associated with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC), some patients experience relapse and succumb to the disease; thus, there is a need for biomarkers identifying these patients for intensified treatment. Leucine-rich repeats and immunoglobulin-like domain (LRIG) protein 1 is a negative regulator of receptor tyrosine kinase signaling and a positive prognostic factor in OPSCC. Studies indicate that LRIG1 interacts with the LIM domain 7 protein (LMO7), a stabilizer of adherence junctions. Its role in OPSCC has not been studied before.

METHODS

A total of 145 patients diagnosed with OPSCC were enrolled. Immunohistochemical LMO7 expression and staining intensity were evaluated in the tumors and correlated with known clinical and pathological prognostic factors, such as HPV status and LRIG1, CD44, Ki67, and p53 expression.

RESULTS

Our results show that high LMO7 expression is associated with significantly longer overall survival (OS) (p = 0.044). LMO7 was a positive prognostic factor for OS in univariate analysis (HR 0.515, 95% CI: 0.267-0.994, p = 0.048) but not in multivariate analysis. The LMO7 expression correlated with LRIG1 expression (p = 0.048), consistent with previous findings. Interestingly, strong LRIG1 staining intensity was an independent negative prognostic factor in the HPV-driven group of tumors (HR 2.847, 95% Cl: 1.036-7.825, p = 0.043).

CONCLUSIONS

We show for the first time that high LMO7 expression is a positive prognostic factor in OPSCC, and we propose that LMO7 should be further explored as a biomarker. In contrast to previous reports, LRIG1 expression was shown to be an independent negative prognostic factor in HPV-driven OPSCC.

p16 and p53 can Serve as Prognostic Markers for Head and Neck Squamous Cell Carcinoma

OBJECTIVE

The present study aimed to explore the expression and clinical significance of human papilloma virus-related pathogenic factors (p16, cyclin D1, p53) in patients with head and neck squamous cell carcinoma (HNSCC) and construct a predictive model.

METHODS

The Cancer Genome Atlas was used to obtain clinical data for 112 patients with HNSCC. Expression of p16, p53, and cyclin D1 was quantified. We used the survival package of the R program to set the cut-off value. Values above the cut-off were considered positive, while values below the cut-off were negative. Kaplan-Meier analysis and univariate and multivariate Cox regression analyses were performed to investigate prognostic clinicopathological indicators and the expression of p16, p53, and cyclin D1. A predictive model was constructed based on the results of multifactor Cox regression analysis, and the accuracy of the predictive model was verified through final calibration analysis. Follow-up of patients with HNSCC at the Affiliated Hospital of Binzhou Medical University was conducted from 2015 to 2017, and reliability of the predictive model was validated based on follow-up data and molecular expression levels.

RESULTS

According to the results, expression of p16 and p53 was significantly associated with prognosis (P < .05). The predictive model constructed based on the expression levels of p16 and p53 was useful for evaluating the prognosis of patients with HNSCC. The predictive model was validated using follow-up data obtained from the hospital, and the trend of the follow-up results was consistent with the predictive model.

CONCLUSION

p16 and p53 can be used as key indicators to predict the prognosis of HNSCC patients and as critical immunohistochemical indicators in clinical practice. The survival model constructed based on p16 and p53 expression levels reliably predicts patient prognosis.

p16 overexpression identifies oncogenic high-risk HPV infection in non-oropharyngeal squamous cell carcinoma of the head and neck

BACKGROUND

Human papillomavirus (HPV) is an increasing risk factor for cancer. HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) is associated with a favorable outcome. Blockstaining for p16 is a surrogate marker for HPV+ OPSCC. In oral and laryngeal squamous cell carcinoma (OSCC/LSCC), the relevance of p16 immunohistochemistry, alone or in combination with other cell cycle-related proteins, to identify HPV-driven non-OPSCC is less well understood.

METHODS

We stained for p16, pRb, cyclin D1, and p53 in 327 HNSCC. In 310 OPSCC, HPV-status was assessed by HPV DNA PCR. In 119 non-OPSCC, RNA in situ hybridization was additionally performed. HPV-status was correlated with staining patterns, p53 and clinical data.

RESULTS

The OPSCC showed blockstaining for p16 in 36%, 8% were equivocal. Of these, HPV-testing was performed in 57%, and 53% were positive for HPV DNA. HPV-association correlated with absence of pRb and cyclin D1 and favorable outcome. In non-OPSCC, 18% showed p16-blockstaining, and 13% showed E6/E7 RNA. Six of seven HPV+ OSCC and 8/8 LSCC lost pRb and cyclin D1. Compared to HPV-negative counterparts, patients with HPV+ cancers had lower rates of alcohol consumption and keratinizing morphology. HPV-positive OSCC had a longer overall survival (p < 0.05). HPV subtype 16 was the most common.

CONCLUSIONS

We conclude that HPV-positive non-OPSCC are associated with p16 overexpression and low levels of pRb and cyclin D1. High expression of pRb and cyclin D1 indicates HPV-negativity.

Genetic Mutations Associated with Inflammatory Response Caused by HPV Integration in Oropharyngeal Squamous Cell Carcinoma

(1) Background: Head and neck cancer (HNC) ranks as the sixth most prevalent cancer in the world. In addition to the traditional risk factors such as alcohol and tobacco consumption, the implication of the human papillomavirus (HPV) is becoming increasingly significant, particularly in oropharyngeal cancer (OPC). (2) Methods: This study is based on a review analysis of different articles and repositories investigating the mutation profile of HPV-related OPC and its impact on patient outcomes. (3) Results: By compiling data from 38 datasets involving 8311 patients from 12 countries, we identified 330 genes that were further analyzed. These genes were enriched for regulation of the inflammatory response (RB1, JAK2, FANCA, CYLD, SYK, ABCC1, SYK, BCL6, CEBPA, SRC, BAP1, FOXP1, FGR, BCR, LRRK2, RICTOR, IGF1, and ATM), among other biological processes. Hierarchical cluster analysis showed the most relevant biological processes were linked with the regulation of mast cell cytokine production, neutrophil activation and degranulation, and leukocyte activation (FDR < 0.001; p-value < 0.05), suggesting that neutrophils may be involved in the development and progression of HPV-related OPC. (4) Conclusions: The neutrophil infiltration and HPV status emerge as a potential prognostic factor for OPC. HPV-infected HNC cells could potentially lead to a decrease in neutrophil infiltration. By gaining a better molecular understanding of HPV-mediated neutrophil immunosuppression activity, it is possible to identify a meaningful target to boost antitumor immune response in HNC and hence to improve the survival of patients with HNC.

Utilization of p53 and p16 Immunohistochemistry in the Classification of Human Papillomavirus-Associated, p53 Wild-Type, and p53 Abnormal Oral Epithelial Dysplasia

p53 immunohistochemistry (IHC) has recently been shown to be a clinically useful marker for predicting risk of progression to invasive squamous cell carcinoma in oral epithelial dysplasia (OED). The literature supports the use of p53 IHC as a marker to identify TP53 mutation in in situ and invasive vulvar lesions and as a surrogate marker for high-risk human papillomavirus (HPV) infection, but there is little documentation for similar use in OED. The purpose of this study was to determine whether p53 IHC is a reliable surrogate marker for detecting both TP53 mutation and high-risk HPV infection in OED. We studied 57 cases of OED (11 mild, 18 moderate, and 28 severe), and all were stained for p16 and p53 IHC. High-risk HPV RNA in situ hybridization (ISH) was performed in selected cases (all p16-positive cases and all OED showing abundant apoptotic cells and karyorrhectic cells; N = 27). Targeted next-generation sequencing (NGS) was performed in 33 p16-negative cases and all high-risk HPV RNA ISH-negative cases (N = 36). We identified 21 cases with p53 basal sparing patterns (mid-epithelial and markedly reduced [null-like]), 14 cases with p53 wild-type patterns (scattered basal and patchy basal/parabasal), and 22 cases with p53 abnormal patterns (18 overexpression, 3 null, and 1 novel cytoplasmic pattern). Among cases with p53 basal sparing patterns, 20 were positive for p16 (20/21, 95%), and all were positive for high-risk HPV RNA ISH (21/21, 100%). The 36 sequenced cases had IHC patterns concordant with TP53 mutation status in 92% (33/36) of lesions. This study demonstrates that p53 IHC expression patterns are sensitive and specific for detection of both high-risk HPV infection and TP53 mutation. Coupled with selective p16 IHC testing, this IHC panel can accurately subclassify OED into HPV-associated, p53 wild-type (conventional), and p53 abnormal OED.

Immunohistochemical Evaluation of p16 and p53 in Oral and Oropharyngeal Squamous Cell Carcinoma with Special Regard to Human Papillomavirus Status

Background

Incidence of human papillomavirus (HPV)-associated oral and oropharyngeal squamous cell carcinomas (OSCC and OPSCC) is on a rising trend globally and has specific therapeutic implications. HPV-related tumors have a distinct pathogenetic mechanism targeting p16 and p53 both. However, there are limited studies evaluating p16 and p53 expression in combination.

Aim

The aim of the study is to evaluate p16 and p53 immunohistochemical expression pattern in OSCC and OPSCC, with special reference to HPV association.

Study Design

This was a hospital-based prospective study done over 22 months (September 2018 to June 2020), including a total of 54 cases of OSCC and OPSCC. They were subjected to clinicopathological evaluation, p16 and p53 immunohistochemistry, and DNA polymerase chain reaction testing for testing of HPV association, followed by analysis of data by statistical methods.

Results

Out of 54, 43 cases were OSCC and 11 cases were OPSCC. A total of nine cases were HPV positive. HPV association was found to be significant with tonsil as primary site, age range between 40 and 60 years, and absence of tobacco or alcohol habit. Presence of HPV infection was also significantly associated with p16 overexpression, in combination with p53 negativity. The findings indicate that p16 overexpression combined with a negative p53 expression can be used for HPV detection and the former alone may be used as diagnostic marker in OPSCC only.

Conclusion

HPV-associated OSCC and OPSCC are a unique subset of cancers, and using combination of molecular biomarkers could help in diagnosis and prognosis.

Classification of Vulvar Squamous Cell Carcinoma and Precursor Lesions by p16 and p53 Immunohistochemistry: Considerations, Caveats, and an Algorithmic Approach

There is emerging evidence that vulvar squamous cell carcinoma (VSCC) can be prognostically subclassified into 3 groups based on human papillomavirus (HPV) and p53 status: HPV-associated (HPV+), HPV-independent/p53 wild-type (HPV-/p53wt), or HPV-independent/p53 abnormal (HPV-/p53abn). Our goal was to assess the feasibility of separating VSCC and its precursors into these 3 groups using p16 and p53 immunohistochemistry (IHC). A tissue microarray containing 225 VSCC, 43 usual vulvar intraepithelial neoplasia (uVIN/HSIL), 10 verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN), and 34 differentiated VIN (dVIN), was stained for p16 and p53. Noncomplementary p16 and p53 patterns were resolved by repeating p53 IHC and HPV RNA in situ hybridization (ISH) on whole sections, and sequencing for TP53. Of 82 p16-positive VSCC, 73 (89%) had complementary p16 and p53 patterns and were classified into the HPV+ group, 4 (4.9%) had wild-type p53 staining, positive HPV ISH and were classified into the HPV+ group, whereas 5 (6.1%) had p53 abnormal IHC patterns (1 null, 4 overexpression), negativity for HPV ISH, and harbored TP53 mutations (1 splice site, 4 missense); they were classified as HPV-/p53abn. Of 143 p16-negative VSCC, 142 (99.3%) had complementary p53 and p16 patterns: 115 (80.4%) HPV-/p53abn and 27 (18.9%) HPV-/p53wt. One had a basal-sparing p53 pattern, positivity for HPV ISH and was negative for TP53 mutations-HPV+ category. The use of IHC also led to revised diagnoses-HSIL to dVIN (3/43), dVIN to vaVIN (8/34), and dVIN to HSIL (3/34). Overall, 215/225 VSCC (95.6%) could be easily classifiable into 3 groups with p16 and p53 IHC. We identified several caveats, with the major caveat being that "double-positive" p16/p53 should be classified as HPV-/p53abn. We propose an algorithm that will facilitate the application of p16 and p53 IHC to classify VSCC in pathology practice.

The Role of the p16 and p53 Tumor Suppressor Proteins and Viral HPV16 E6 and E7 Oncoproteins in the Assessment of Survival in Patients with Head and Neck Cancers Associated with Human Papillomavirus Infections

The role of HPV in the survival prognosis of patients with head and neck squamous cell carcinoma, especially patients with laryngeal squamous cell carcinoma (LSCC) and hypopharyngeal squamous cell carcinoma (HPSCC), is still somewhat ambiguous. The present study aimed to explore the significance of tumor suppressor proteins and HPV16 E6 and E7 oncoproteins in the assessment of survival in patients with oropharyngeal squamous cell carcinoma (OPSCC), LSCC, and HPSCC associated with high-risk (HR-) and low-risk (LR-) HPV infections. By utilizing molecular and immunohistochemical investigations of HNSCC samples and patient data, univariate and multivariate survival analyses were conducted. The presence of HPV DNA (LR- and HR-HPV) was associated with a better 5-year OS and DSS for OPSCC and LSCC. The IHC overexpression of HPV16 E6 protein and p16 protein was associated with better survival in the univariate (for OPSCC) and multivariate (OPSCC and HPSCC) survival analyses. The overexpression of p53 was associated with better survival in OPSCC. HPV infection plays a significant role in the tumorigenesis of HNSCC, and the immunohistochemical assessment of HPV16 E6 protein expression should be interpreted as a useful prognostic marker for OPSCC and HPSCC.

Prognostic stratification of oropharyngeal cancer patients in a betel nut chewing and low HPV area

BACKGROUND

This study aimed to establish a simple predictive model for oropharyngeal cancer (OPC) in an area with a relatively low prevalence of human papillomavirus (HPV) and frequent betel nut chewing.

METHODS

A total of 116 patients with OPC were recruited from the clinical research database of a referral cancer center between 2013 and 2018. Patient characteristics-including age, gender, tumor stage, differentiation, and treatment modality-were extracted from the database. Patients diagnosed after 2018 were staged using the 7th AJCC staging system to explore the impact of extra-nodal tumor extension (ENE) on survival. Immunohistochemical analysis was performed for p16, epidermal growth factor receptor (EGFR), p53, and programmed cell death ligand 1 (PD-L1). ENE status was evaluated by pathological analysis or radiological features. Primary outcome was disease-specific overall survival (OS). Univariate and multivariate Cox regression were used to establish a predictive model.

RESULTS

Mean age was 57.3 ± 9.9 years; 103 patients (88.8%) were male. P16 positive OPC was positively associated with higher PD-L1 and a tonsillar sub-site and negatively associated with betel nut chewing and cigarette smoking. In Cox regression, age, p16 status, EGFR, cT4, ENE, and cigarette smoking were significantly associated with OS. In survival tree analysis, cT stage was the most important risk stratification parameter, followed by EGFR expression and p16 status. Patients with cT4 stage or high EGFR were classified as the high-risk group and had poorest OS.

CONCLUSIONS

Due to the low prevalence of HPV and popularity of betel nut chewing in Asia, the relative importance of prognostic predictors for OPC are not identical to Western countries. Identification of significant prognostic biomarkers may improve treatment. Trial registration This study was registered and approved by the Institutional Review Board (IRB) of Kaohsiung Veterans General Hospital (VGHKS19-CT9-07; date of approval: Aug 9, 2019).

Accuracy of p16 IHC in Classifying HPV-Driven OPSCC in Different Populations

High-risk human papillomavirus (HPV) infection is a defined etiopathogenetic factor in oropharyngeal carcinogenesis with a clear prognostic value. The P16 IHC (immunohistochemistry) is a widely accepted marker for HPV-driven carcinogenesis in oropharyngeal squamous cell carcinoma (OPSCC); in the present paper, we discuss its reliability as a standalone marker in different populations. The literature suggests that rates of p16 IHC false positive results are inversely correlated with the prevalence of HPV-driven carcinogenesis in a population. We propose a formula that can calculate such a false positive rate while knowing the real prevalence of HPV-driven OPSCCs in a given population. As it has been demonstrated that p16 positive/HPV negative cases (i.e., false positives at p16 IHC) have the same prognosis as p16 negative OPSCC, we conclude that despite the valuable prognostic value of p16 IHC, relying only on a p16 IHC positive result to recommend treatment de-intensification could be risky. For this aim, confirmation with an HPV nucleic acid detection system, especially in areas with a low prevalence of HPV-related OPSCCs, should be pursued.

Human papillomavirus-related neoplasia of the ocular adnexa

Human papillomaviruses (HPV) are involved in approximately 5% of solid cancers worldwide. The mucosotropic genotypes infect the stratified epithelium of various locations, where persistent infection may lead to invasive carcinomas. While the causative role of HPV in certain anogenital and head and neck carcinomas is well established, the role of HPV in carcinomas arising in the mucosal membranes of the ocular adnexal tissue (the lacrimal drainage system and the conjunctiva) has been a topic of great uncertainty. Therefore, we conducted a series of studies to assess the correlation between HPV and carcinomas arising in the mucosa of the ocular adnexal tissue and characterize the clinical, histopathological, and genomic features of the tumors in the context of HPV status in a Danish nationwide cohort. We collected clinical and histopathological data and tumor specimens from patients with carcinomas of the conjunctiva and the lacrimal drainage system, and their potential precursors, identified in Danish nationwide registries. The HPV status of the tumors was determined by the combined use of HPV DNA polymerase chain reaction (PCR), HPV E6/E7 mRNA in-situ hybridization, and p16 immunohistochemistry. The genomic profile was investigated by high-throughput DNA sequencing targeting 523 cancer-relevant genes. The literature to date on carcinomas of the lacrimal drainage system and the conjunctiva was summarized. In the Danish cohort, 67% of all carcinomas of the lacrimal drainage system and 21% of all conjunctival carcinomas were HPV-positive. HPV16 was the most frequently implicated genotype. A full-thickness expression of the viral oncogenes E6 and E7 was evident in almost all HPV DNA-positive cases. The HPV-positive carcinomas of the conjunctiva and the lacrimal drainage system shared histopathological and genomic features distinct from their HPV-negative counterparts. The HPV-positive carcinomas were characterized by a non-keratinizing morphology, p16 overexpression, high transcriptional activity of HPV E6/E7, and frequent pathogenic variants in the PI3K-AKT signaling cascade. In contrast, the HPV-negative carcinomas were characterized by a keratinizing morphology, lack of p16 and E6/E7 expression, and frequent somatic pathogenic variants in TP53, CDKN2A, and RB1. Among the patients with conjunctival tumors, HPV positivity was associated with a younger age at diagnosis and a higher risk of recurrence. In conclusion, the results support an etiological role of HPV in a subset of conjunctival and LDS carcinomas and their precursor lesions. Our investigations have shown that the HPV-positive carcinomas of the ocular adnexa share genomic and phenotypic characteristics with HPV-positive carcinomas of other anatomical locations. Therefore, these patients may be eligible for inclusion in future basket trials and future treatment regimens tailored to the more frequently occurring HPV-positive carcinomas of other locations. Future research will further elucidate the diagnostic, prognostic, and predictive role of HPV in these carcinomas.

Low Prevalence of HPV Related Oropharyngeal Carcinogenesis in Northern Sardinia

HPV infection is a clear etiopathogenetic factor in oropharyngeal carcinogenesis and is associated with a markedly better prognosis than in smoking- and alcohol-associated cases, as specified by AJCC classification. The aim of the present work is to evaluate the prevalence of HPV-induced OPSCC in an insular area in the Mediterranean and to assess the reliability of p16 IHC (immunohistochemistry) alone, as accepted by AJCC, in the diagnosis of HPV-driven carcinogenesis in such a setting. All patients with OPSCC consecutively managed by the referral center in North Sardinia of head and neck tumor board of AOU Sassari, were recruited. Diagnosis of HPV-related OPCSS was carried out combining p16 IHC and DNA testing on FFPE samples and compared with the results of p16 IHC alone. Roughly 14% (9/62) of cases were positive for HPV-DNA and p16 IHC. Three more cases showed overexpression of p16, which has a 100% sensitivity, but only 75% specificity as standalone method for diagnosing HPV-driven carcinogenesis. The Cohen’s kappa coefficient of p16 IHC alone is 0.83 (excellent). However, if HPV-driven carcinogenesis diagnosed by p16 IHC alone was considered the criterion for treatment deintensification, 25% of p16 positive cases would have been wrongly submitted to deintensified treatment for tumors as aggressive as a p16 negative OPSCC. The currently accepted standard by AJCC (p16 IHC alone) harbors a high rate of false positive results, which appears risky for recommending treatment deintensification, and for this aim, in areas with a low prevalence of HPV-related OPSCC, it should be confirmed with HPV nucleic acid detection.

Understanding the Pattern of Oropharyngeal Cancers from North-East Romanian Patients

Background: Human papilloma virus (HPV) is acknowledged as a risk factor for oropharyngeal squamous cellular cancers (OPSCC), of which the dominant types are tonsillar (TSCC) and base of tongue cancer (BOTSCC). Objective: To assess the role of HPV in selected OPSCC cases, from Romanian patients by sensitive and complementary molecular assays. Material and Methods: Fifty-four formalin fixed paraffin embedded (FFPE) OPSCC samples were analyzed for HPV DNA by a PCR-based bead-based multiplex-assay. Thirty-four samples were tested for HPV RNA and for overexpression of p16INK4a by immunohistochemistry. Twenty samples were evaluated by Competitive Allele-Specific Taqman PCR (CAST-PCR) for fibroblast growth factor receptor 3 protein (FGFR3) status. Results: A total of 33.3% (18/54) OPSCC samples were positive for HPV DNA. HPV16 was the most frequent type (30%, 16/54); followed by HPV18 (3.7%, 2/54); and 1 sample (1.8%) was positive for both HPV16 and 18. HPV18 E6*I was detected in a HPV18 DNA-positive oropharynx tumor. Four samples positive for HPV16 were also positive for p16INK4a. All the tested samples were negative for FGFR3. Conclusions: The increased HPV16 prevalence is in line with similar studies and is a new confirmation that HPV16 is the most prevalent type in our country; supporting the potential benefit of prophylactic vaccines. Overall, there is no concordance between DNA and any of the two other analytes that are considered being markers of HPV-driven cancers. There is a need to explore novel screening strategies that could be broadly used in the clinical routine to initiate preventive measures.

Relevance of Human Papillomaviruses in Head and Neck Cancer-What Remains in 2021 from a Clinician's Point of View?

Human papillomaviruses (HPV) cause a subset of head and neck cancers (HNSCC). HPV16 predominantly signs responsible for approximately 10% of all HNSCC and over 50% of tonsillar (T)SCCs. Prevalence rates depend on several factors, such as the geographical region where patients live, possibly due to different social and sexual habits. Smoking plays an important role, with non-smoking patients being mostly HPV-positive and smokers being mostly HPV-negative. This is of unparalleled clinical relevance, as the outcome of (non-smoking) HPV-positive patients is significantly better, albeit with standard and not with de-escalated therapies. The results of the first prospective de-escalation studies have dampened hopes that similar superior survival can be achieved with de-escalated therapy. In this context, it is important to note that the inclusion of p16^INK4A (a surrogate marker for HPV-positivity) in the 8th TMN-classification has only prognostic, not therapeutic, intent. To avoid misclassification, highest precision in determining HPV-status is of utmost importance. Whenever possible, PCR-based methods, still referred to as the "gold standard”, should be used. New diagnostic antibodies represent some hope, e.g., to detect primaries and recurrences early. Prophylactic HPV vaccination should lead to a decline in HPV-driven HNSCC as well. This review discusses the above aspects in detail.

Lymphoepithelial carcinoma of the parotid gland: a unique example showing p16 immunoreactivity

Lymphoepithelial carcinoma (LEC) shows characteristic histology of nesting growth of tumor cells with unclear differentiation against the lymphoid stroma background. Although rare in salivary glands, it has previously been recognized as a type of undifferentiated carcinoma but is currently clearly defined as an independent disease separate from undifferentiated carcinoma. We report a case of LEC that developed in the parotid gland and was immunohistochemically positive for p16, which suggested the causative involvement of human papillomavirus (HPV). The patient was a 38-year-old Japanese male aware of mass formation in the left parotid area for 8 years. Parotidectomy was performed and there have been no signs of recurrence or metastasis for 18 month post-operation. The tumor was histologically typical except for Epstein-Barr virus (EBV)-encoded small RNA (EBER)-negative in situ hybridization (ISH), but p16-positivity by immunohistochemistry, and also frequent contact with extended and expanded pre-existing ductal structures. Although usually strongly associated with EBV infection, the tumor could be regarded to have eventually reached completion as a LEC lesion associated with HPV infection possibly through the pathway shared with squamous cell carcinoma. EBER-ISH remains the most promising index for confirming diagnosis of LEC, but EBV-negative result alone should not prevent diagnosis of LEC.