Abstract
Oral cancers, i.e. those which affect the mouth, possess a number of features which, despite the relative ease with which the mouth can be visually and palpably examined, add yet more layers of complexity to the detection, diagnosis and treatment of these cancers. One such factor is the tendency for benign, potentially malignant and cancerous lesions to be similar upon visual inspection. Another is the often asymptomatic development of oral cancers, which often go undetected by patients until the point of metastatic spread. A number of factors contribute to the early diagnosis and successful treatment of oral cancers, however, in this thesis, the researcher focused on the following: detection of lesions as dysplastic or cancerous, potentially at an early stage of cancer development, by using minimally invasive sampling and testing methods. Samples of oral tissue were collected from patients with cancerous and potentially malignant lesions, and healthy participants, using brush biopsies. Cells collected from the mouths of patients and participants were then tested using a label-free technique employed to elucidate the electrophysiological properties of said cells by exposing them to alternating current electric fields, known as dielectrophoresis or DEP. Dielectrophoresis was also used to characterise a sub-group of cells reported to drive tumour formation, metastasis and treatment evasion-cancer stem cells. Specifically, this thesis contains work on the use of collagen IV adherence as an oral cancer stem-ness biomarker, and the evaluation of oral cancer stem cells with epithelial and the more motile, mesenchymal phenotype. In summary, the work presented here forms three, main studies in which dielectrophoresis was used to explore key factors involved in the potential for successful diagnosis of oral cancers-early detection leading to early diagnosis, and the characteristics of cancer stem cells.