[Prophylactic and therapeutic vaccines against human papilloma virus]

[Recurrent laryngeal papillomatosis]

Human papillomaviruses (HPV) 6 and 11 cause 90% of recurrent laryngeal papillomatosis (RLP). It is unclear whether recurrences are caused by new infections or the spread of infected cells. Symptomatic and sometimes curative treatment is laser surgery or conventional microsurgical removal. RLP surgery aims to relieve shortness of breath and improve the voice. Patients (especially children) are affected by voice problems, repetitive surgeries, pulmonary manifestations, and psychological trauma. Vaccination with Gardasil 9 (Merck & Co., Rahway, NJ, USA) prevents new infections with HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58 and induces vaccine antigen-specific antibodies and CD4+ T helper cells. According to current studies, RLP can be avoided with prophylactic vaccination. The treatment is associated with a general vaccination risk (European Medicines Agency approval: girls and boys from 9 years). Studies also show that the vaccine after removal of HPV-associated neoplasia/papilloma prevents recurrences. Extension of the vaccination recommendation to prevent recurrences of HPV-associated diseases in men may promote applicability and herd immunity. For rare and treatment-refractory cases with laryngotracheal involvement, systemic therapy with bevacizumab (e.g. Avastin; Genentech, San Francisco, CA, USA), a VEGF antibody, is a promising adjuvant treatment option.

Phenotype of p53 wild-type epitope-specific T cells in the circulation of patients with head and neck cancer

CD8⁺ cytotoxic T-cell (CTL) specific for non-mutated, wild type (wt) sequence p53 peptides derived from wt or mutant p53 molecules expressed in head and neck squamous cell carcinomas (HNSCC) have been detected in the circulation of patients with this disease. The frequency and differentiation/maturation phenotypes of these anti-tumor specific CTL can reflect the host’s immunologic response. Therefore, we investigated the frequency and phenotypes of wt sequence p53 peptide-specific CTL in patients with HNSCC (n = 33) by flow cytometric analysis using HLA-A*0201 tetrameric peptides (tet) complexed with the wt sequence p53_264–272 or p53_149–157 peptide and co-staining with phenotypic markers. One main finding was that increasing frequencies of tet⁺ CD8⁺ T cells in patients’ circulation correlated with increased frequencies of inactive naïve tet⁺ cells, while those with effector memory and terminally differentiated phenotypes, which are associated with positive anti-tumor immune responses, decreased. We also found that the frequency of circulating tet⁺ CD8⁺ T cells negatively correlated with p53 expression in tumor tissues and tumor stage. Our findings support further clinical-based investigations to define the frequencies and phenotypes of wt sequence p53 peptide-specific CD8⁺ T cells to predict disease severity, enhance selection of patients for inclusion in vaccination trials and highlight prerequisites to enhance immune susceptibility by activation of inactive naïve tet⁺ T cells and/or enhancing circulating effector T cell activity by checkpoint blockage.

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.