Background: Oral Tongue Squamous Cell Carcinoma (OTSCC) is the most frequent and aggressive carcinoma in the head and neck region. Its incidence has increased during the last decades, especially in young patients (≤40 years) mainly female. These young patients have either not been exposed to the traditional risk factors for this disease, or have a much reduced duration of exposure than the typical OTSCC patient. The reasons behind this increasing incidence remain unknown. The aims of this thesis were to analyse the presence and possible role of human papillomavirus (HPV) in oral tongue cancer in correlation with its surrogate marker p16 and its receptor syndecan-1. Other aims were to evaluate expression of EMT (epithelial to mesenchymal transition) - related markers, such as E-cadherin, β-catenin, CK5 and CK19, and to address the potential predictive role of podoplanin in the loco-regional metastatic process. Clinical parameters including age, sex, geographical distribution, relapse, tumour staging and grading were also investigated for a possible correlation with biomarker expression and prediction of survival rate and therapeutic strategy. Materials and methods: More than one hundred samples of OTSCC coming from two University Hospitals of two different countries (Sweden and Italy) were analysed. HPV presence was evaluated by in situ hybridisation for detection of the high-risk HPV 16 and indirectly by immunohistochemistry (IHC) of its surrogate marker p16. Expression of the HPV receptor syndecan-1 and the EMT biomarkers E-cadherin, β-catenin, CK5, CK19 were also evaluated by immunohistochemistry. Samples were scored using a quick score (QS), taking both number and intensity of cells stained into account. Podoplanin expression was investigated at both protein and RNA level. Results: Tumour size and lymph node metastasis correlated to both overall and disease-free survival. Despite variable expression of the syndecan-1 receptor, HPV 16 was not detected in any sample analysed, excluding a possible association with p16, which was expressed in 33% of the cases. All EMT-related markers were commonly expressed in tongue cancer. Data showed E-cadherin to be an independent prognostic factor with higher expression associated with poor overall survival. Notably, E-cadherin, β-catenin and CK5 directly correlated to each other. Multivariate analysis of clinical data demonstrated that age of the patient is an independent prognostic factor with younger patients showing a worse survival rate. Patients younger than 40 years also showed significantly higher expression of podoplanin. Data for geographic distribution revealed a difference in expression of E-cadherin between Swedish and Italian patients. Conclusions: In contrast to SCC of the base of the tongue and the tonsil, HPV is not present in OTSCC, excluding HPV infection as a risk factor. Higher levels of E-cadherin and young age is associated with poor survival in OTSCC patients. The different frequency of EMT markers seen between Swedish and Italian patients suggests an important role for the environment and the geographical area in the onset of different molecular patterns of OTSCC.

Yes / Recently a sub-population of cells with stem cell characteristics, reported to be associated with initiation, growth, spread and recurrence, has been identified in several solid tumors including oral tongue squamous cell carcinoma (OTSCC). The aim of our pilot study was to isolate CD44+ cancer stem cells from primary cultures of OTSCC and neck node Level I (node-I) biopsies, grow cell spheres and observe their characteristics in primary cultures. Parallel cultures of hyperplastic lesions of tongue (non-cancer) were set up as a control. Immunohistochemistry was used to detect CD44/CD24 expression and magnetic activated cell sorting to isolate CD44+ cell populations followed by primary cell culturing. Both OTSCC and node-I biopsies produced floating spheres in suspension, however those grown in hyperplastic and node-I primary cultures did not exhibit self-renewal properties. Lymph node metastatic OTSCC, express higher CD44/CD24 levels, produce cancer cell spheres in larger number and rapidly (24 hours) compared to node negative OTSCC (1 week) and non-cancer specimens (3 weeks). In addition, metastatic OTSCC have the capacity for proliferation for up to three generations in primary culture. This in vitro system will be used to study cancer stem cell behavior, therapeutic drug screening and optimization of radiation dose for elimination of resistant cancer cells. / SKMCH&RC, Yorkshire Cancer Research

Head and neck cancer is a heterogeneous group of tumours, of which certain subgroups such as cancer of the mobile tongue frequently are associated with a relatively poor prognosis due to the high risk of regional failure and mortality rates that haven’t improved in a significant way over the last 3 decades, despite advancements in both diagnostics and treatment. Today we lack means to assess the biological aggressiveness of each individual tumour, which varies largely. Treatment comprises of surgery with additional radiotherapy and medical therapies in more advanced tumours. The focus in this thesis is on molecular biomarker expression in head and neck cancer and especially in association with radiotherapy. Increased knowledge paves the way to a more individualized cancer treatment aiming for better outcome and less overtreatment and sequelae. The aims of this thesis was: To map the effects of radiotherapy in both tumour and adjacent tissue for the possible markers hyaluronan, EGFR and mast cells. To investigate whether the expression of hyaluronan in the epithelium and connective tissue stroma and EGFR in the tumour correlates with the risk for developing cervical metastasis in N0 patients, and to find out whether the 3-year tumour-specific survival rates correlates with the expression of HA in the epithelium and EGFR in the tumour. To establish an animal model for radiation-induced mucositis and to use that model to examine the pattern of invading inflammatory cells. To investigate whether the expression of podoplanin in tongue cancer correlates with the risk for cervical metastasis and to determine whether the total amount of lymph vessels in the diagnostic biopsy has any impact on the clinical outcome. To investigate the differences in the metabolome of tongue cancer cell lines with different radiosensitivity. The most important findings of this thesis were: The expression of EGFR and hyaluronan hade the same pattern of expression in both tumour and adjacent tissues before radiotherapy. The expression of EGFR was increased in the epithelium of the adjacent tissue close to the tumour after radiotherapy. The intensity of the staining of hyaluronan was correlated to the 3-year survival rates in patients with tongue cancer. An experimental model for radiation-induced oral mucositis in rat was established and in this model a temporal pattern of macrophage invasion with two different subtypes of macrophages was found. There were no correlation between the expression of podoplanin in the tumour tissue and the cervical metastasis rate in patients with tongue cancer, but the younger patients were more likely to have a higher expression of podoplanin in their tumour than elder patients. Tongue cancer cell lines with different radiosensitivity respond to irradiation with different patterns of metabolic expressions.

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