Findings from a Malaysian multicentre study on oropharyngeal squamous cell carcinoma.

BACKGROUND: In addition to the conventional aetiologic agents of oropharyngeal squamous cell carcinoma (OPSCC) such as tobacco usage, alcohol consumption and betel quid usage, it has been established that a proportion of OPSCC are driven by persistent oncogenic human papillomavirus (HPV) infections. Currently, there is a lack of data on the burden of HPV- associated OPSCC in Asian countries including Malaysia. 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. RESULTS: From the cases identified, 184 cases had sufficient tissue material for analysis. Overall, median age at diagnosis was 63.0 years (IQR = 15) and 76.1% of patients were males. In our cohort, 35.3% of patients were Indian, 34.2% were Chinese, 21.2% were Malay and 9.2% were from other ethnicities. The estimated prevalence of HPV-associated OPSCC in our cohort was 31.0% (CI 24.4-38.2%). The median age for the HPV-associated OPSCC sub-group of patients was not significantly lower than the median age of patients with HPV-independent OPSCC. More than half of HPV-associated OPSCC was seen in patients of Chinese ethnicity (54.4%). Patients with HPV-associated OPSCC had a much better overall survival than patients with HPV-independent OPSCC (Log rank test; p < 0.001). Patients with HPV-associated OPSCC with no habit-related risk factors such as smoking, were found to have much better overall survival when compared to all other sub-groups. CONCLUSIONS: The findings from our study suggests that prevalence of HPV-associated OPSCC in Malaysia, though not as high as some developed countries, is however on an upward trend. HPV-associated OPSCC appears to be more frequently encountered in patients of Chinese ethnicity. Conventional risk-factors associated with OPSCC such as smoking, alcohol consumption and betel quid chewing should still be considered when estimating prognosis of patients with HPV-associated OPSCC.

Knowledge, attitude and practice of patients towards orthodontic treatment.

BACKGROUND: Orthodontic treatment is a time-consuming and highly technique-sensitive clinical procedure. A patient's comprehension and compliance with oral hygiene instructions and appliance maintenance are critical to the success of orthodontic treatment. This study was performed to assess the knowledge, attitude and practice of patients seen at government orthodontic clinics in the Federal Territories of Kuala Lumpur and Putrajaya towards orthodontic treatment. 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. CONCLUSIONS: The orthodontic patients in the Federal Territories of Kuala Lumpur and Putrajaya possess good knowledge about their treatment however their attitude and orthodontic related practices need to be improved.

Transcriptional analysis highlights three distinct immune profiles of high-risk oral epithelial dysplasia.

Oral potentially malignant disorders (OPMD) are precursors of oral squamous cell carcinoma (OSCC), and the presence of oral epithelial dysplasia (OED) in OPMD confers an increased risk of malignant transformation. Emerging evidence has indicated a role for the immune system in OPMD disease progression; however, the underlying immune mechanisms remain elusive. In this study, we used immune signatures established from cancer to delineate the immune profiles of moderate and severe OED, which are considered high-risk OPMD. We demonstrated that moderate and severe OEDs exhibit high lymphocyte infiltration and upregulation of genes involved in both immune surveillance (major histocompatibility complex-I, T cells, B cells and cytolytic activity) and immune suppression (immune checkpoints, T regulatory cells, and tumor-associated macrophages). Notably, we identified three distinct subtypes of moderate and severe OED: immune cytotoxic, non-cytotoxic and non-immune reactive. Active immune surveillance is present in the immune cytotoxic subtype, whereas the non-cytotoxic subtype lacks CD8 immune cytotoxic response. The non-immune reactive subtype showed upregulation of genes involved in the stromal microenvironment and cell cycle. The lack of T cell infiltration and activation in the non-immune reactive subtype is due to the dysregulation of CTNNB1, PTEN and JAK2. This work suggests that moderate and severe OED that harbor the non-cytotoxic or non-immune reactive subtype are likely to progress to cancer. Overall, we showed that distinct immune responses are present in high-risk OPMD, and revealed targetable pathways that could lead to potential new approaches for non-surgical management of OED.

The clinical utility of contemporary oral epithelial dysplasia grading systems.

INTRODUCTION: Clinical management of oral potentially malignant disorders relies on accurate histopathological assessment of the presence and grade of oral epithelial dysplasia. While adjunctive laboratory tests have provided useful prognostic information, none are in widespread clinical use. This study was performed to assess the clinical utility of two contemporary oral epithelial dysplasia grading systems. 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. CONCLUSION: This study demonstrates that the WHO 2017 and binary grading systems are reproducible between calibrated pathologists and that consensus reporting is likely to improve the consistency of grading. The WHO and binary systems were prognostically comparable. We recommend that institutions implement consensus oral epithelial dysplasia grading and prospectively audit the effectiveness of risk stratifying their patients with oral potentially malignant disorders. (249 words).

Predicting the clinical outcome of oral potentially malignant disorders using transcriptomic-based molecular pathology.

BACKGROUND: This study was undertaken to develop and validate a gene expression signature that characterises oral potentially malignant disorders (OPMD) with a high risk of undergoing malignant transformation. 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]. CONCLUSIONS: This study demonstrates proof of principle that RNA extracted from FFPE diagnostic biopsies of OPMD, when analysed on the NanoString nCounter platform, can be used to generate a molecular classifier that stratifies the risk of malignant transformation with promising clinical utility.

Clinico-pathological study of malignant odontogenic tumours from a national referral centre.

BACKGROUND: Malignant odontogenic tumours are extremely rare tumours occurring within the jaws. Our study was performed to determine the demographic and clinico-pathological features of malignant odontogenic tumours amongst a multi-ethnic Asian population. 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. CONCLUSIONS: Diagnosis and management of malignant odontogenic tumours are challenging due to the rarity of these tumours. Our study has elucidated the clinico-pathological features of malignant odontogenic tumours seen in a multi-ethnic Asian population.

Dysplasia and DNA ploidy to prognosticate clinical outcome in oral potentially malignant disorders.

BACKGROUND: Oral potentially malignant disorders are a clinical conundrum as there are no reliable methods to predict their behaviour. We combine conventional oral epithelial dysplasia grading with DNA ploidy analysis to examine the validity of this approach to risk assessment in a cohort of patients with known clinical outcomes. 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." RESULTS: Ninety cases were included in the study. Seventy cases yielded informative DNA ploidy results. Of these 70 cases, 31 progressed to cancer. Oral epithelial dysplasia grading and DNA ploidy status were both significantly associated with clinical outcome (P < 0.05). Severe dysplasia had a hazard ratio of 3.50 (CI: 1.46, 8.45; P = 0.005) compared to cases with mild dysplasia. Aneuploidy had a hazard ratio of 2.09 (CI: 1.01, 4.32; P = 0.046) compared to cases with a diploid/tetraploid status. Receiver operating characteristic analysis gave an area under the curve of 0.617 for DNA ploidy status and 0.688 when DNA ploidy status was combined with dysplasia grading. CONCLUSION: Our findings suggest that combining dysplasia grading with DNA ploidy status has clinical utility which could be used to develop novel management algorithms.

Monoamine oxidase A is down-regulated in EBV-associated nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we identify for the first time a role for monoamine oxidase A (MAOA) in NPC. MAOA is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines. Depending on the cancer type, MAOA can either have a tumour-promoting or tumour-suppressive role. We show that MAOA is down-regulated in primary NPC tissues and its down-regulation enhances the migration of NPC cells. In addition, we found that EBV infection can down-regulate MAOA expression in both pre-malignant and malignant nasopharyngeal epithelial (NPE) cells. We further demonstrate that MAOA is down-regulated as a result of IL-6/IL-6R/STAT3 signalling and epigenetic mechanisms, effects that might be attributed to EBV infection in NPE cells. Taken together, our data point to a central role for EBV in mediating the tumour suppressive effects of MAOA and that loss of MAOA could be an important step in the pathogenesis of NPC.

Concurrent HPV-related oropharyngeal carcinoma in four couples.

OBJECTIVES: Typically, HPV-related cancers are sexually transmitted, however, the natural history of HPV-related oropharyngeal squamous cell carcinoma (OPSCC) is unclear. HPV16 transmission has been reported previously between five couples with OPSCC. We report the clinico-pathological features of a further four couples with HPV-related OPSCC and compare them with the published cases. PATIENTS AND METHODS: We identified four couples in long-term heterosexual relationships that all had HPV-related OPSCC. The couples were treated at three UK hospitals and presented between 2009 and 2015. HPV tests included p16 immunohistochemistry, high-risk HPV DNA in-situ hybridisation and Roche Cobas HPV test. DNA sequencing was used to determine the HPV variant. RESULTS: The four couples represented < 2% of patients with HPV-related OPSCC at the three contributing hospitals (8 of 457 consecutive patients). The couples' tumours all contained HPV16. The mean age was 63 years old (range 52-72 years). The interval between the index cancer and the partner's cancer was 16, 24, 26 and 64 months respectively. The majority of patients had Stage I disease (UICC TNM8). Six of eight patients are disease free, one patient is alive with disease and there was one death from loco-regional recurrence. CONCLUSION: This report highlights the occurrence of HPV-related OPSCC in heterosexual couples and raises the possibility of transmission of HPV16. Despite increasing prevalence of HPV-related OPSCC and increased awareness of the disease, there is a paucity of couples with the disease, suggesting either under-reporting or that the development of OPSCC following HPV transmission between couples is a rare event.

Clinico-pathological features of oropharyngeal squamous cell carcinomas in Malaysia with reference to HPV infection.

BACKGROUND: The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has been rising in Western countries and this has been attributed to human papillomavirus (HPV) infection. p16 expression is a marker for HPV infection and p16 positive OPSCC is now recognized as a separate disease entity. There are only limited data available regarding HPV-related OPSCC in Asian countries and no data from Malaysia. 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. CONCLUSION: The proportion of OPSCCs associated with HPV in Malaysia appears to be lower than in European and American cohorts and could possibly be more prevalent amongst Malaysians of Chinese ethnicity. Further, our data suggests that the burden of HPV-related OPSCC could be increasing in Malaysia. Larger cross-sectional studies of Malaysian patients are required to determine the public health implications of these preliminary findings.

Trigeminal neuralgia: a retrospective multicentre study of 320 Asian patients.

OBJECTIVES: This study was performed to obtain the clinicodemographic data regarding patients with trigeminal neuralgia (TN) treated at oral-maxillofacial medicine clinics, as there is a paucity of such information in the Asian setting. STUDY DESIGN: Retrospective multicenter study involving clinicodemographic information of 320 patients with TN diagnosed between 2001 and 2012 at eight regional oral-maxillofacial medicine clinics and followed up for at least 6 months. Statistical tests were performed to assess the associations among the clinicodemographic factors. RESULTS: TN was mostly diagnosed during the seventh and sixth decades of life, with a median of 58.2 years (interquartile range = 13.0). Females were more commonly affected (61.6%). TN affected the right side more frequently, and the mandibular branch was most commonly involved (58.5%). Carbamazepine was the first-line drug of choice (87.5%). CONCLUSIONS: Asian patients with TN exhibited features similar to those in Caucasian patients except for the increased affliction of the mandibular division.