Head and neck cancer (HNC) makes up 6 ¢H of the cancer patients in the world every year. This disease usually occurs in males and the incidence is increasing year by year. According to statistical analysis, HNC has less than 50 ¢H five-year survival rate. Therefore, the research of HNC seems imminent so that may lead to the development of new approaches of diagnosis and therapy. Recent research had shown that expression of podoplanin caused cellular proliferation, and may be associated with tumor invasion, metastasis and malignant prognosis. Podoplanin, a mucin-type transmembrane sialoglycoprotein, is highly expressed in lymphatic endothelial cells but not expressed in vascular endothelial cells. The purpose of this study was to determine the clinical and pathological significance of podoplanin in oral squamous cell carcinoma (OSCC). Therefore, we collected clinical specimen and associated patient history of OSCC. Further, we used the human cell lines of HNSCC (Fadu, Hep2) to investigate the molecular regulation of podoplanin. Podoplanin expression was analyzed by RT-PCR and Western blot assay firstly. As shown, podoplanin was found to be overexpressed in tumors compared with normal adjacent tissues. Further, immunohistochemical analysis revealed the location of podoplanin expression in OSCC tissues. The results showed that podoplanin had higher expression in T4 stage tumor section than in normal adjacent tissues of OSCC samples, or in T1 stage. Here, podoplanin was highly expressed in the OSCC tumor cell and lymphatics of stage T4 OSCC tissue. Furthermore, we found that overexpression of podoplanin in OSCC patients was associated with decreased five-years survival rate. In the univariate analysis, several factors were statistically significantly associated with disease-specific survival rate, including Tumor stage, Nodal stage, and podoplanin expression. In the subsequent multivariate analysis, only Tumor stage and Nodal stage showed a trend toward worse disease-specific survival. To further investigate the regulatory mechanism of podoplanin and its position of expression within the cell, immunofluorescence and transfection were utilized to assay. The results showed that podoplanin was expressed in the nuclear membrane of the Fadu and Hep2 cell lines, and the PI3K/AKT signaling pathway was involved. We suggest that the role of podoplanin in OSCC should be further investigated for potential future treatment.

Cisplatin is an effective chemotheraputic agent for head and neck squamous cell carcinoma particularly in conjunction with radiation therapy. Unfortunately, its cytotoxic profile and associated systemic side effects limit its clinical efficacy. A localized delivery system was developed for cisplatin by processing calcium polyphosphate (CPP) in a multistep gelling protocol, with the goal of limiting its systemic toxicity and enhancing its overall clinical applicability. In addition, a novel method for processing the material was examined utilizing cold isostatic pressure (CIP) to allow for miniaturization of the system into an implantable device. The integration of cisplatin into the matrix was examined for efficient and dose dependent loading via dissolution of the final product and measurement of platinum concentrations by inductively coupled plasma optical emission spectrometry (ICP-OES). Drug release was measured in vitro by placing the CPP-cisplatin matrix into TRIS buffer solution while measuring the platinum concentration at given intervals from 0.5 hours to 14 days. The cytotoxicity of the cisplatin against L1210 cells was examined using an MTT assay following a 12-hour elution. The material demonstrated a predictable and dose dependent loading of cisplatin, although the release of the drug showed variability exemplified by a more pronounced burst release with aging of the stock CPP glass particulate. The CPP/cisplatin matrix exhibited cytotoxic effects after processing. This work suggests that further evaluation of this material as a matrix for cisplatin delivery should be undertaken in an attempt to normalize release, maximize the concentration within the system and further optimize the bead format in order to improve the potential for clinical usage.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 132-174) Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2008.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 132-174) Also available online.

Thesis (Ph.D.) - University of Queensland, 2002. / Includes bibliography.

Thesis (M.Phil.) - University of Queensland, 2005. / Includes bibliography.

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (cSCC) and desmoplastic melanoma (DM) may be a negative prognostic finding, and likely contributes to increased rates of local recurrence. The biological mechanisms underlying PNI remain unclear, although several lines of evidence implicate neurotrophins and their receptors. Expression of the high affinity nerve growth factor (NGF) receptor TrkA has been shown to be associated with PNI in numerous malignancies, although literature in cutaneous neoplasms is sparse. Given this, we sought to ascertain the incidence of PNI in a cohort cSCCs using double immunostaining (DIS), and to investigate PNI's relationship with TrkA expression and established histopathologic prognosticators. In DMs we investigated the relationship between TrkA and PNI. In DM we additionally analyzed expression of the low affinity NGF receptor (p75NGFR) and the presence of a functional polymorphism in the glial cell line-derived neurotrophic factor (GDNF) receptor RET (RETp) as they relate to PNI. In this IRB approved study, cSCCs from the head and neck (H&N) and 53 from non-H&N areas were immunohistochemically analyzed for PNI (DIS with S100 and p63) and TrkA expression. For DM, 43 cases were immunohistochemically evaluated for TrkA and p75NGFR expression while RETp was detected by direct DNA sequencing. The presence of each was correlated with histologically observed PNI. In cSCCs, comparing H&N versus non-H&N areas; using hemotoxylin and eosin (H&E) PNI was detected in 11% versus 6% of cases respectively and using DIS, in 23% versus 15% respectively, with significant disagreement between both methods (𝜅=0.47, p=0.002). There was a 2.33 fold increase in PNI detection with DIS compared to H&E (95%CI: 1.12-4.87; p=0.02). TrkA expression was 2.9 times more frequently observed in cSCCs from the H&N compared to those from non-H&N areas (p=0.01). Regardless of site, TrkA expression was associated with decreased degree of differentiation (OR=6.46, p=0.0006) and high-risk morphologic variants (OR = 6.53, p=0.002). TrkA expression was not significantly associated with PNI (p=0.33). In DM, PNI was present in 67% of cases. On univariate analysis; p75NGFR was associated with PNI (expression detected in 79% of PNI-positive cases compared to 36% of PNI-negative cases, p=0.005), increased Breslow's depth and greater Clark's Level (p= 0.007 and p= 0.01 respectively). RETp was noted in 28% of cases but was not significantly associated with PNI (p=0.27) or other histopathologic variables. TrkA expression was absent in all cases. PNI was associated with increased Breslow's depth and Clark's Level (p=0.01 and p=0.009 respectively). Controlling for the association between p75NGFR and depth, p75NGFR remained associated with an increased propensity for PNI (OR=4.68, p=0.04). In conclusion, increased PNI detection with DIS in cSCCs underscores the adjunctive utility of immunohistochemistry in microstaging. Although unlikely to play a role in the development of PNI, TrkA's association with cSCCs from H&N and select histopathologic parameters suggests a role for the NGF-TrKA axis in tumorogenesis while its absent expression in DM suggests that expression is lineage-related. Lastly, In DM, p75NGFR expression is significantly associated with PNI and a more locally aggressive phenotype.

Magister Scientiae Dentium - MSc(Dent) / Background: Recent epidemiological reports established that there is an increase in the incidence of oral squamous cell carcinoma in young patients. Some report this to be in the absence of contributing habits such as smoking and alcohol use. Few reports of such a nature have reported a similar trend in South Africa. Aim: Describe the epidemiological pattern of oral squamous cell carcinoma seen at the Tygerberg academic complex. Method: Histopathological biopsy reports of patients diagnosed by the oral pathology department of Tygerberg hospital from 1996 to 2013 were electronically retrieved and included. Patients were grouped by age into two groups, one included patients 40 years and younger, the other included patients older than 40 years. Descriptive analysis was performed for age, sex, smoking and alcohol habits and oral site of tumor. Frequency of OSCC patients was calculated manually from the total number of oral biopsies. Chi- square or Fisher’s exact tests were used as appropriate. Probabilities of less than 0.05 were regarded as significant. Results: The total number of OSCC patients over the 18-year period was 2220. The mean age was 57.6years.The male to female ratio was 2.9:1 for all age groups and 2.2:1 for young patients. The majority of patients (96%) were above 40 years old. Smoking and alcohol were commonly reported for all age groups (91.3%) and (83.8%) for young patients. The tongue was the commonest site for all age groups (30.8%) followed by oropharynx (27.3%) while in younger patients, the oropharynx was the commonest site (30.3%) followed by tongue (29.2%). Conclusion: The study confirmed that OSCC is still an affliction of people older than 40 years and males are predominantly affected. Smoking and alcohol are strong risk factors for OSCC irrespective of patient's age. OSCC among people older than 40 years may have no great difference from the same disease affecting younger ones in terms of sex, oral habits and tumor site.