[Human papillomavirus and cancer of the oropharynx. Molecular interaction and clinical implications]

[Update for Diagnosis and Management of HPV-Driven Oropharyngeal Cancer]

Update for Diagnosis and Management of HPV-Driven Oropharyngeal Cancer Abstract. In the past decades, an increasing incidence of oropharyngeal squamous cell cancer could be observed. More than twenty years ago, a correlation between a pharyngeal Human papillomavirus high-risk type infection and the development of oropharyngeal cancer has been suspected. Especially younger patients without the former risk factors smoking and alcohol have a higher prevalence for this cancer type. HPV-associated cancer is developing in the lymphatic tissue of the tonsils and the base of the tongue. HPV-driven tumors can be defined as a clinical and morphologic distinct tumor entity with a significantly better prognosis compared to tumors based on smoking and alcohol consumption. They are demonstrating a clearly better treatment response irrespective of the treatment modality. The tumor development is assumed to be comparable to cervical cancer, probably through a step-wise process from dysplasia to invasive cancer. In the pharynx, no HPV-associated precursor lesions have been detected so far. Therefore, Screening program proven to be very successful in the cervix have not could not have been implemented so far. The reduction of HPV-associated tumor burden in the cervix is likely to be compensated by the rising number of HPV-driven oropharyngeal cancer. P16 as a surrogate marker for HPV has been implemented in the 8th edition of the TNM classification for oropharyngeal cancer. A worldwide accepted definition of an HPV-driven tumor is lacking so far. P16 immunhistochemistry or HPV-DNA detection by PCR as single markers have an insufficient sensitivity and specificity. A combination of both markers demonstrates a higher accuracy compared to the gold standard RNA. Antibodies to HPV oncoproteins are reliable diagnostic and prognostic markers that could in the future possibly serve for early tumor detection.

Epidemiologic associations of HPV-positive oropharyngeal cancer and (pre)cancerous cervical lesions

Human papillomavirus (HPV)-induced oropharyngeal squamous cell carcinoma (OPSCC) remains increasing worldwide. We aimed to investigate if the HPV-prevalence of OPSCC in the Netherlands is rising as well, also in female patients. In addition, we evaluated the association between HPV-positive OPSCC and suspicious Pap results of the cervix in these female patients. Patients with OPSCC treated in the period 2000-2015 at the VU University Medical Center Amsterdam, were included (n = 926). The presence of an oncogenic HPV infection was determined by p16-immunostaining, followed by a high-risk HPV general primer 5+/6+ DNA PCR on the p16-immunopositive cases. A review of pathology reports in all female patients (n = 305) was undertaken to identify cytological signs of HPV-related (pre)cancer of the cervix. In total 281 of 926 (30.3%) OPSCCs were HPV-positive. Moreover, a significant increase in the prevalence of HPV-positive OPSCCs was observed from 14.0% in 2000 to 48.1% in 2015 (p < 0.001). Among the female patients with an HPV-positive OPSSC (n = 70), the results of cervical smears were available in 56 of 70 patients (80.0%). Of the female patients with HPV-positive OPSCC, 9 of 56 (16.1%) patients had a vaginal cuff Papanicolaou (Pap) test ≥3b in their medical history compared to 7 of 168 (4.2%) in the HPV-negative group (p = 0.003). In conclusion, a continuous increase in the HPV-attributable fraction of OPSCC was demonstrated in the period 2000-2015 in the Amsterdam region. HPV-positive OPSCC has a significant association with a history of suspicious Pap results of the cervix in female patients.

Variation of HPV Subtypes with Focus on HPV-Infection and Cancer in the Head and Neck Region

The human papillomavirus (HPV) comprises a heterogeneous group of double-strand DNA viruses with variable potential to infect human epithelial cells and trigger neoplastic transformation. Its 8 kb genome encodes proteins required for virus replication and self-organized formation of infectious particles but also for early proteins E6 and E7 able to trigger neoplastic transformation. E6 and E7 of high-risk (HR) HPV subtypes can bind to p53 or release E2F and abrogate replication control. Due to variable amino acid sequence (AAS) in the binding sites of E6 and E7 particular HR-HPV variants within subtypes are essentially heterogeneous in efficacy triggering neoplastic transformation and cancer development. This could explain differences in the clinical course of HPV-driven head and neck cancer.

[HPV infection in oral, pharyngeal and laryngeal papillomas]

BACKGROUND

HPV infections play a major role in the pathogenesis of squamous cell carcinomas of the head and neck. Regarding benign papillomas, the role of HPV is still uncertain.

MATERIALS AND METHODS

To clarify this issue, 100 exophytic papillomas of the oral cavity, pharynx and larynx were subjected to histopathological and molecular pathological examination. Excision biopsies were taken from 62 male and 38 female patients with an age range of 18 to 87 years. Biopsies were tested for p16 expression by immunohistochemistry and analyzed for HPV subtypes 6/11 (low-risk), 16/18 and 31/33/53 (high-risk) by chromogenic in situ hybridization.

RESULTS

HPV infections were verified molecularly in 34 % of biopsies; in all cases with the low-risk HPV subtypes 6/11. Only one case showed infection with both 6/11 and 31/33/53 subtypes, but not subtype 16/18; whereas expression of p16 was found in 67 %. The rate of positive molecular verification of HPV infection (in situ hybridization) was highest in the laryngeal lesions with 61.1 %, followed by the oral cavity with 52.9 %, and lowest in pharyngeal lesions (21.5 %). Recurrent papillomas were seen in 18 cases (18 %), of which 14 were molecularly positive for HPV (in situ hybridization). A correlation between inflammatory infiltration and HPV infection could be verified in 82 %.

CONCLUSION

Our data demonstrate an important role of HPV infection for the development of benign papillomas of the head and neck region. Furthermore, there is a positive correlation between HPV infection and recurrent papillomas. Therefore, a molecular morphological HPV analysis of papillomas could provide important prognostic data.

Lapatinib-induced mesenchymal-epithelial transition in squamous cell carcinoma cells correlates with unexpected alteration of β-catenin expression

The epithelial-mesenchymal transition (EMT) is a key developmental program that is often activated during cancer progression, and may promote resistance of cancer cells to therapy. Inhibiting EMT appears to be crucial to inhibit drug resistance. The mesenchymal-epithelial transition (MET), which is the reverse program of EMT in metastases, is characterized by the upregulation of epithelial adhesive proteins such as E-cadherin, and downregulation of mesenchymal proteins such as vimentin. The sensitivity of cancer cells to epithelial growth factor receptor (EGFR) inhibitor may be increased by inducing MET in these cells. Therefore, it is of clinical importance to specify the phenotype of cancer cells in order to overcome the phenomenon of drug resistance. The aim of the present study was to investigate the expression pattern of specific markers in squamous cell carcinoma (SCC) cells following stimulation with lapatinib and gefitinib. For this purpose, the head and neck (HN) SCC cell lines HNSCC22B and HNSCC11A were incubated with 0.5 and 2 µg/ml lapatinib and gefitinib, and the levels of E-cadherin, vimentin, matrix metalloproteinase-14, c-kit and β-catenin were detected by immunocytochemistry and enzyme-linked immunosorbent assay at 5, 24 and 96 h post-incubation. The results indicated that, compared with HNSCC22B cells, the protein expression levels of vimentin increased, whereas those of E-cadherin reduced, in non-stimulated HNSCC11A cells. In addition, the protein expression levels of β-catenin were altered in the epithelial- and mesenchymal-associated SCC cell lines following treatment with lapatinib and gefitinib. Furthermore, lapatinib induced the downregulation of vimentin and upregulation of E-cadherin in HNSCC11A cells in a time-dependent manner. This suggests that the sensitivity of cancer cells to lapatinib may be improved by inducing MET in these cells. In summary, the results of the present study demonstrated that lapatinib-induced MET led to an unexpected alteration of the protein expression levels of β-catenin in SCC cells. Further studies on the mechanistic role of MET are required in order to increase the sensitivity of cancer cells to EGFR inhibitor and block the EMT process in these cells.

[Targeting p16(INK4a) by therapeutic vaccination : Concept and status of clinical investigations in HPV-associated head and neck cancers]

BACKGROUND

Up to 70% of oropharyngeal cancers are attributable to human papillomavirus (HPV) infection; however, a therapy specific for patients with HPV-associated cancers is currently not available. Overexpression of the viral oncogenes E6 and E7 results in cellular alterations that represent interesting targets for novel therapies. One consequence of E6/E7 overexpression is strong expression of the cellular protein p16(INK4a). The elimination of p16(INK4a)-expressing tumor cells by the immune system could be achieved through a therapeutic p16(INK4a) vaccine.

OBJECTIVE

The current article provides an overview of HPV-associated head and neck cancers and the associated p16(INK4a) expression. Based on this overview, the concept and status of the clinical investigation of therapeutic p16(INK4a) vaccination is described.

MATERIAL AND METHODS

In addition to discussing published literature, a clinical study is described. In this phase I/IIa study, patients with advanced HPV-associated p16(INK4a)-expressing tumors were vaccinated with a p16(INK4a) peptide.

RESULTS

HPV-associated head and neck cancers continuously display strong overexpression of the cellular protein p16(INK4a). Vaccination with p16(INK4a) could represent a novel therapy for patients with HPV-associated carcinomas.

CONCLUSION

Further studies will evaluate the clinical efficacy of therapeutic p16(INK4a) vaccination. Combinations with other immunotherapeutic approaches are interesting considering the modulating role of the immune system, particularly in HPV-associated tumors.

Prognostic factors in oral and oropharyngeal cancer based on ultrastructural analysis and DNA methylation of the tumor and surgical margin

Oral and oropharyngeal cancers are characterized by relatively low 5- year survival rates due to many factors, including local recurrence. The identification of new molecular markers may serve for the estimation of prognosis and thus augment treatment decisions and affect therapy outcome. The aim of this study was to describe the morphological characteristics and the DNA methylation status of the CDKN2A,CDH1, ATM, FHIT and RAR- genes in the central and peripheral part of the tumor and the surgical margin and evaluate their prognostic significance. 53 patients with oral and oropharyngeal cancer were enrolled to the prospective study, and had been primarily treated surgically. Correlations between morphological data, hypermethylation status and clinicopathological data, as well as prognosis, were assessed. Nuclei polymorphism highly correlated with T stage (p < 0.0001), N stage (p < 0.046), and metastases to the lymph nodes pN (p < 0.004 ). Also, the number of cells in irregular mitosis correlated with T stage (p < 0.004), and highly with pN (p < 0.009). The significance of CDKN2A hypermethylation as a good prognostic factor was also established in the Kaplan-Meir test. The ultrastructural analysis showed that none of the examined tumors had homogenous texture and that resection margin specimens clean in HE stained tissue samples frequently contained single tumor cells or few cells in groups surrounded by connective tissue. This indicates the superiority of electron microscopy over standard histopathological analysis. Thus, a combination of such morphological examination with epigenetic parameters described herein could result in the discovery of promising new prognostic markers of the disease.

[HPV-associated oropharyngeal carcinoma. Status quo and relationship with cancer of unknown primary]

Carcinomas of the oropharynx with association to high-risk types of human papillomavirus (HPV) have been identified as a new tumour entity with favourable prognosis, distinct from classical nicotine- and alcohol-associated carcinoma. They develop through oncogenic transformation of the basal cells of reticulated cryptal epithelium of the palatinal tonsils and the base of the tongue. Positivity for HPV strongly correlates with an atypical, non-keratinizing histological differentiation and cystic transformation of lymph node metastases. Strong immunohistological positivity for p16 reliably detects transcriptionally active infection with high-risk HPV. Hence, p16 staining has been regarded as an effectual diagnostic tool in the appropriate setting. Frequent nodal metastasation as well as considerable size of (cystic) metastases, and frequent small size as well as submucosal location of primary tumours all contribute to frequent initial manifestation of cervical cancer of unknown primary (CUP). In a situation of CUP diagnostic testing for HPV (in negative cases in addition to EBV) is recommended in lymph node metastases, due to the high predictive value for the localization of occult primary carcinomas. Intense clinicopathological cooperation is mandatory for improved detection of small, occult primary carcinomas. The relevance of this new carcinoma entity will increase, as the incidence continues to increase worldwide.

[The visionary concept of "lymphoepithelioma" by A. Schmincke in 1921. Subsequent confusion over terminology and current approach to a solution]

In 1921 Alexander Schmincke established the visionary concept of a clinically and histomorphologically defined carcinoma entity of different lymphoepithelial organs that he named "lymphoepithelioma". This nowadays mainly comprises non-keratinizing oropharyngeal carcinomas frequently associated with human papillomavirus (HPV) and non-keratinizing nasopharyngeal carcinomas mostly associated with Epstein-Barr virus (EBV). The term lymphoepithelioma was originally defined by A. Schmincke and J. Ewing as a combined clinical and histological tumor entity of lymphoepithelial organs. The main reason for the longstanding terminological confusion regarding the term lymphoepithelioma is based on the fact that lateron a pure histological interpretation (lymphoepithelial differentiation) caused an artificial and nonreproducible exclusion of tumors with transitional and basaloid differentiation. For the forthcoming new WHO classification it has been suggested that squamous cell carcinoma of the head and neck should no longer be classified according to the heterogeneous histological differentiation but according to etiopathogenetic criteria (e.g. HPV-related, EBV-related, nicotine and alcohol-related). This proposed classification corresponds much better to the prognosis and therapy and would represent a late acknowledgement of Schmincke's visionary concept of a clinically and histomorphologically defined tumor entity. In addition, the ongoing terminological confusion over the heterogeneous and prognostically weak spectrum of histological differentiation would subside.

[Human papillomavirus in squamous cell cancer of the head and neck. A study at the Ulm Military Hospital, Germany]

There is increasing evidence worldwide that human papillomavirus is a major risk factor for head and neck cancer. Only few studies on this association have been performed in Germany to date. For the purposes of the present study, tumor specimens from 223 patients with squamous cell cancer of the oral cavity, oropharynx, hypopharynx and larynx were analyzed for HPV DNA and p16INK4a expression. The prevalence of HPV genotype 16 (HPV16) DNA in the study population was 17.5%. Further high-risk HPV types were not detected. All HPV16-positive tumors showed intense p16INK4a expression. HPV16 prevalence was highest in tonsillar carcinoma (37.5%) and lowest in laryngeal cancer (2.8%). We observed a significantly higher incidence of cervical lymph node metastases in patients with HPV16-positive tonsillar carcinoma in comparison to HPV-negative tumors (p < 0.016). Tobacco and/or alcohol consumption was significantly lower in patients with HPV-positive tumors (p < 0.0001).

Transoral treatment strategies for head and neck tumors

The introduction of transoral endoscopic surgery has initiated a fundamental change in the treatment of head and neck cancer. The endoscopic approach minimizes the intraoperative trauma. Due to the lower burden for the patient and the savings potential these methods have gained wide acceptance. These transoral accesses routes allow experienced surgeons to reduce the morbidity of surgical resection with no deterioration of oncologic results. This suggests a further extension of the indication spectrum and a high growth potential for these techniques and equipment in the coming years. For selected patients with selected tumors the minimally invasive transoral surgery offers improved oncological and functional results. In the present paper, different surgical access routes are presented and their indications discussed.

Basics of tumor development and importance of human papilloma virus (HPV) for head and neck cancer

Head and Neck Squamous Cell Carcinomas (HNSCC) are the 6(th) most common cancers worldwide. While incidence rates for cancer of the hypopharynx and larynx are decreasing, a significant increase in cancer of the oropharynx (OSCC) is observed. Classical risk factors for HNSCC are smoking and alcohol. It has been shown for 25 to 60% of OSCC to be associated with an infection by oncogenic human papilloma viruses (HPV). The development of "common" cancer of the head and neck is substantially enhanced by an accumulation of genetic changes, which lead to an inactivation of tumor suppressor genes or activation of proto-oncogenes. A more or less uniform sequence of different DNA-damages leads to genetic instability. In this context, an early and frequent event is deletion on the short arm of chromosome 9, which results in inactivation of the p16-gene. In contrast, for HPV-induced carcinogenesis, expression of the viral proteins E6 and E7 is most important, since they lead to inactivation of the cellular tumor-suppressor-proteins p53 and Rb. The natural route of transoral infection is a matter of debate; peroral HPV-infections might be frequent and disappear uneventfully in most cases. Smoking seems to increase the probability for developing an HPV-associated OSCC. The association of HNSCC with HPV can be proven with established methods in clinical diagnostics. In addition to classical prognostic factors, diagnosis of HPV-association may become important for selection of future therapies. Prognostic relevance of HPV probably surmounts many known risk-factors, for example regional metastasis. Until now, no other molecular markers are established in clinical routine. Future therapy concepts may vary for the two subgroups of patients, particularly patients with HPV-associated OSCC may take advantage of less aggressive treatments. Finally, an outlook will be given on possible targeted therapies.

Systemic therapy strategies for head-neck carcinomas: Current status

Head and neck cancers, most of which are squamous cell tumours, have an unsatisfactory prognosis despite intensive local treatment. This can be attributed, among other factors, to tumour recurrences inside or outside the treated area, and metastases at more distal locations. These tumours therefore require not only the standard surgical and radiation treatments, but also effective systemic modalities. The main option here is antineoplastic chemotherapy, which is firmly established in the palliative treatment of recurrent or metastatic stages of disease, and is used with curative intent in the form of combined simultaneous or adjuvant chemoradiotherapy in patients with inoperable or advanced tumour stages. Neoadjuvant treatment strategies for tumour reduction before surgery have yet to gain acceptance. Induction chemotherapy protocols before radiotherapy have to date been used in patients at high risk of distant metastases or as an aid for decision-making ("chemoselection") in those with extensive laryngeal cancers, prior to definitive chemoradiotherapy or laryngectomy. Triple-combination induction therapy (taxanes, cisplatin, 5-fluorouracil) shows high remission rates with significant toxicity and, in combination with (chemo-)radiotherapy, is currently being compared with simultaneous chemoradiotherapy; the current gold standard with regards to efficacy and long-term toxicity.A further systemic treatment strategy, called "targeted therapy", has been developed to help increase specificity and reduce toxicity. An example of targeted therapy, EGFR-specific antibodies, can be used in palliative settings and, in combination with radiotherapy, to treat advanced head and neck cancers. A series of other novel biologicals such as signal cascade inhibitors, genetic agents, or immunotherapies, are currently being evaluated in large-scale clinical studies, and could prove useful in patients with advanced, recurring or metastatic head and neck cancers. When developing a lasting, individualised systemic tumour therapy, the critical evaluation criteria are not only efficacy and acute toxicity but also (long-term) quality-of-life and the identification of dedicated predictive biomarkers.

Increasing prevalence rates of HPV attributable oropharyngeal squamous cell carcinomas in the Netherlands as assessed by a validated test algorithm

Human papillomavirus (HPV) infection has been etiologically linked to oropharyngeal squamous cell carcinoma (OPSCC). The prevalence of HPV-positive OPSCC varies between studies, ranging from 20 to 90%. This may be related to the lack of a standardized HPV detection assay as well as to the time period in which HPV prevalence is investigated, as rising incidence rates are reported over the last decades. Here, we validated our previously defined test algorithm for HPV detection in formalin-fixed paraffin-embedded (FFPE) tumor specimen consisting of p16(INK4A) immunostaining followed by high-risk HPV DNA detection by GP5+/6+ PCR on the positive cases (Smeets et al., Int J Cancer 2007;121:2465-72). In addition, we analyzed HPV prevalence rates in OPSCCs in the years 1990-2010. The test algorithm was validated on a consecutive series of 86 OPSCCs collected during 2008-2011, of which both fresh frozen and FFPE samples were available. We performed HPV-E6 RT-PCR on the frozen samples as gold standard and applied the algorithm to the corresponding FFPE samples. The test algorithm showed an accuracy of 98%. Using the validated algorithm, we determined the presence of an oncogenic HPV infection in 240 OPSCCs of patients diagnosed in the years 1990-2010 at our center. A significant increase in the proportion of HPV-positive samples was observed, from 5.1% in 1990 to 29.0% in 2010 (p = 0.001). In conclusion, we confirmed the accuracy of the test algorithm for HPV detection in FFPE tumor specimen and we found a significant increase in the prevalence of HPV in OPSCC over the last two decades at our center.

Prognostic impact of human papillomavirus status, survivin, and epidermal growth factor receptor expression on survival in patients treated with radiochemotherapy for very advanced nonresectable oropharyngeal cancer

BACKGROUND

The influence of human papillomavirus (HPV) status on survival for patients with very advanced inoperable oropharyngeal SCC treated with radiochemotherapy (RCT) was studied.

METHODS

Patients received either 69.2 Gy with concomitant boost (ccb) or 70 Gy conventionally fractionated (cf), weekly paclitaxel 40 mg/m(2), and carboplatin area under the concentration-time curve (AUC) 1. Tumor was analyzed for the presence of high-risk HPV-DNA using polymerase chain reaction (PCR) and direct DNA sequencing. p16-expression, survivin, and epidermal growth factor receptor (EGFR) expression were evaluated by immunohistochemistry and influence on survival was calculated.

RESULTS

Of 52 patients, 25.0% were HPV positive and 75.0% HPV negative. The 2-year progression-free survival (PFS) was 70.1% for p16-positive patients and 37.1% for p16-negative patients (p = .005). The 3-year overall survival (OS) rate was 43.9% for all patients and did not significantly differ between the groups. Neither survivin nor EGFR expression influenced PFS or OS significantly.

CONCLUSIONS

HPV status influences PFS in patients with advanced, nonresectable tumor stages but not OS. Additional risk factors seem to have a stronger influence on survival than HPV status.

[Update on HPV-induced oropharyngeal cancer]

Oropharyngeal squamous cell carcinoma (OSCC) is associated with oncogenic human papillomavirus (HPV) infection in 30-40% of all cases in Germany. The use of PCR and / or in situ hybridisation to detect HPV in tumour tissue is used in combination with p16 immunohistochemistry to reliably distinguish HPV-related and HPV-unrelated OSCC. The distinct biological behaviour of the HPV-related subset of OSCC results in a more favourable prognosis. This might be the result of a greater response to chemotherapy and radiotherapy as seen in recent studies. Ongoing and future clinical trials will stratify for HPV status. If the results of these prospective, randomized trials are consistent with the preliminary results of recent studies, HPV status will be of enormous clinical relevance in the future.

[HPV-associated head and neck cancer. The basics of molecular and translational research]

Translational research refers to the interfaces between preclinical research and targeted short- and medium-term developments through to clinical standards. There are two distinct groups of oropharyngeal malignancies: those caused by tobacco and alcohol abuse and those caused by HPV infection. Although the prognosis of patients in the latter group is significantly better, this is not taken into consideration in the choice of treatment. However, less intensive use of radiotherapy, chemotherapy, or surgery, as well as targeted multimodal therapeutic approaches, is under research. This article summarizes the main events in the HPV life cycle, with emphasis on carcinogenic mechanisms and potential new molecular targets. Identifying distinct tumor entities of the oropharynx enables the design and development of new preventive and therapeutic strategies to reduce the incidence and mortality of HPV-associated oropharyngeal cancers in the near future.

[Prophylactic and therapeutic vaccines against human papilloma virus]

Infection with human papilloma virus (HPV) has been identified as the cause of recurrent papillomatosis and of a subgroup of squamous cell carcinomas of the head and neck. A change in prevalence of these lesions, especially for oropharyngeal carcinoma, can be expected as a consequence of the introduction of prophylactic HPV vaccines for young women, targeting the most frequent high- and low-risk HPV subtypes. Vaccination for the major low-risk HPV types has proven to be highly effective against genital warts and activity against papillomatosis can be expected. The possibilities of prophylactic HPV vaccination as well as new developments and the rationale for therapeutic vaccines are discussed on the basis of the current literature.

HPV status in head and neck tumors

HPV infection has been associated with head and neck carcinoma (HNSCC). In the present study, a tumor collective from Middle Germany was analyzed using two HPV-detection methods, i.e., PCR followed by agarose gel electrophoresis and microarray chip hybridization. In addition, the predictive value of tumor morphology was assessed. In total, 76 HNSCCs from 52 patients were examined, including 23 pairs of primaries and corresponding metastases. The highest rate of positive tumors was observed in the tonsils, with 76% of the patients and 81% of tumor samples being positive for high-risk HPV. DNA chip analysis detected significantly more HPV-positive cases than did agarose gel electrophoresis. Except for one HPV-33-positive case, all others tumors harbored HPV 16. There was a good concordance between the HPV status of the primary tumor and its corresponding metastasis (21/23 cases, 91%). In two cases, HPV was found only in the primary tumor but not in the metastasis. Our results clearly confirmed the high prevalence of HR-HPV in tonsillar carcinomas with a rate that was even 20% higher than those reported in the literature. Morphology is a valuable indicator for an HPV association that needs to be confirmed by molecular tests.