METHODS: This was a retrospective cross-sectional study of malignant odontogenic tumours diagnosed at the Institute for Medical Research, Malaysia, from 2009 to 2019. All cases were independently reviewed and reclassified following the criteria set out in the latest edition of the World Health Organization 2017 reference text. Demographic and clinico-pathological data were recorded for each case.

RESULTS: Twenty-four cases of malignant odontogenic tumours were identified. The patients' age ranged from 16 to 79 years with the mean age at diagnosis being 50.8 years (SD = 16.18). There was a male predominance (66.7%) in this cohort of patients. The ethnic distribution appeared to reflect the Malaysian population with most cases seen amongst the Malay ethnic group (66.7%). Ameloblastic carcinoma was the most frequently diagnosed malignant odontogenic tumour (45.8%) and was also predominantly seen in males (90.9%). All patients with clear cell odontogenic carcinoma were females. There was no obvious sex predilection in primary odontogenic carcinoma not otherwise specified (NOS). The mandible (79.2%) was more frequently involved compared to the maxilla.

METHODS: A retrospective study of 325 patients with head and neck squamous cell carcinoma (HNSCC) treated at one institution between January 1, 1999, and December 31, 2008, was conducted. Outcome measure was the presence/absence of ORNJ. Time to event was recorded and Cox proportional hazard regression analysis was used to determine statistically significant predictive factors.

RESULTS: Fifty-nine patients had ORNJ. Statistical analysis using Cox regression analysis identified several statistically significant variables: dentoalveolar surgery; peri-resective surgery of the jaw; continued tobacco usage after radiotherapy, diabetes mellitus type 2 (DM2); and total radiation dose.

METHODS: Patients were identified from a clinical database. Oral epithelial dysplasia grading was performed by three oral and maxillofacial pathologists blinded to clinical outcome using the WHO 2017 system and a binary classification. The primary outcome measure was the development of oral squamous cell carcinoma, termed 'malignant transformation'.

RESULTS: One hundred thirty-one cases satisfied the inclusion criteria, of which 23 underwent malignant transformation. There was substantial inter-rater agreement between the study pathologists for both grading systems, measured using kappa statistics (κ = 0.753 - 0.784). However, there was only moderate agreement between the consensus WHO 2017 dysplasia grade for the study against the original grade assigned by a pool of six pathologists in the context of the clinical service (κ = 0.491). Higher grade categories correlated with an increased risk of developing cancer using both grading systems.

METHODS: A validated, bilingual, self-administered questionnaire comprising fifteen questions across the domains of Knowledge, Attitude and Practice was used and responses were assessed with 3 responses; one correct, one incorrect and one reflecting uncertainty. 507 patients from five orthodontic centres participated in this study. Data was analysed using SPSS. Continuous data was summarised as mean and standard deviation or median and inter-quartile range, as appropriate. Categorical data was summarised as frequency and percentage, then univariable analysis was carried out with Pearson's chi-square test or Fisher's exact test, as appropriate.

RESULTS: The mean age of respondents was 22.5 years (SD ± 2.8). A majority of respondents were female (64.1%) and from the lowest income bracket or B40 group (71%). Overall, for the knowledge domain, a majority of the respondents got all questions correct. 69.4% of patients were aware that incomplete treatment could lead to worsening of their malocclusion. 80.9% of respondents were aware of the need for a retainer upon completion of their orthodontic treatment. For the attitude section, 64.7% felt that they had to wait a very long time to see the orthodontist. In the Practice domain, the majority only got two of the five questions correct. Only 39.8% of respondents made an effort to alter dietary habits all of the time. In general, females and those with tertiary education fared better for all three domains.

METHODS: Sections from diagnostic biopsies were assessed for oral epithelial dysplasia using the WHO grading system, and DNA ploidy analysis was performed using established methods. Patients reviewed for a minimum of 5 years who did not develop oral squamous cell carcinoma were classified as "non-transforming" cases. Patients that developed oral squamous cell carcinoma ≥ 6 months after the initial diagnostic biopsy were classified as having "malignant transformation."

METHODS: Total RNA was extracted from formalin-fixed paraffin-embedded tissue biopsies of 20 OPMD cases with known clinical outcomes (10 MT vs. 10 NT). Samples were assessed for quantity, quality and integrity of RNA prior to sequencing. Analysis for differential gene expression between MT and NT was performed using statistical packages in R. Genes were considered to be significantly differentially expressed if the False Discovery Rate corrected P-value was  1.90). Analysis of RNA-Sequencing outputs revealed 41 genes (34 protein-coding; 7 non-coding) that were significantly differentially expressed between MT and NT cases. The log2 fold change for the statistically significant differentially expressed genes ranged from -2.63 to 2.48, with 23 protein-coding genes being downregulated and 11 protein-coding genes being upregulated in MT cases compared to NT cases.

METHODS: Patients with oral epithelial dysplasia at one hospital were selected as the 'training set' (n = 56) whilst those at another hospital were selected for the 'test set' (n = 66). RNA was extracted from formalin-fixed paraffin-embedded (FFPE) diagnostic biopsies and analysed using the NanoString nCounter platform. A targeted panel of 42 genes selected on their association with oral carcinogenesis was used to develop a prognostic gene signature. Following data normalisation, uni- and multivariable analysis, as well as prognostic modelling, were employed to develop and validate the gene signature.

RESULTS: A prognostic classifier composed of 11 genes was developed using the training set. The multivariable prognostic model was used to predict patient risk scores in the test set. The prognostic gene signature was an independent predictor of malignant transformation when assessed in the test set, with the high-risk group showing worse prognosis [Hazard ratio = 12.65, p = 0.0003].

Methods: We identified 60 Malaysian patients with OPSCC over a 12-year period (2004-2015) from four different hospitals in two major cities, Kuala Lumpur and Penang. The detection of HPV was carried out using p16 immunohistochemistry and high risk HPV DNA in situ hybridisation.

Results: Overall, 15 (25%) tumours were p16 positive by immunohistochemistry, 10 of which were also positive for high risk HPV DNA by in situ hybridisation. By comparison, a matched cohort of UK patients had a p16 positive rate of 49%. However, between 2009 and 2015, where cases were available from all four hospitals, 13 of 37 (35%) cases were p16 positive. In our Malaysian cohort, 53% of patients were of Chinese ethnicity and 80% of the p16 positive cases were found in these patients; no Indian patients had p16 positive disease, despite representing 35% of the total cohort.

METHODS: A cross-sectional multicentre study with tissue analysis of Malaysian patients diagnosed with primary OPSCC within a five-year period, from 2015 to 2019 between 01/01/2015 to 31/12/2019 was undertaken. Determination of HPV status was carried out using p16INK4a immunohistochemistry on tissue microarrays constructed from archived formalin-fixed paraffin-embedded tissue.