Displaying publications 1 - 20 of 72 in total

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  1. Gunjal S, Pateel DGS, Yang YH, Doss JG, Bilal S, Maling TH, et al.
    Subst Use Misuse, 2020;55(9):1533-1544.
    PMID: 32569533 DOI: 10.1080/10826084.2019.1657149
    Background: Areca nut (AN) and betel quid (BQ) chewing are ancient practices followed by an extensive proportion of the world's population. These practices are endemic in larger parts of South and Southeast Asia and selected Western Pacific countries. The prevalence of these habits varies across regions, age, gender, cultural practice, and socioeconomic status groups. Considerable variations exist between countries with respect to prevention/intervention programs, and policy guidelines of BQ usage. Objectives: (1) To provide an overview of the BQ chewing prevalence, practices, preventive interventions and policies in selected Asian and Western Pacific countries. (2) To explore the different terminologies associated with BQ use. Method: A narrative review of the current literature related to BQ, AN, and oral cancer was conducted by searching PUBMED, CINAHL, and GOOGLE databases. Results: The literature review revealed that the prevalence of BQ was found to be highest in Papua New Guinea, followed by Bangladesh, India, Pakistan, Myanmar and Sri Lanka. While, Cambodia, Malaysia, Indonesia and Taiwan had comparatively lower prevalence. Smokeless tobacco, BQ with tobacco, BQ without tobacco, AN were some of the terminologies used for BQ in various studies. Conclusions: The prevalence, and the interventional policies related to BQ and AN chewing habits varies widely among the selected countries. With the increasing awareness and association of BQ with oral cancer, there is a need to have better awareness, prevention and interventional strategies in place. We also found considerable variation in the use of terminologies associated with BQ.
  2. Lee CE, Vincent-Chong VK, Ramanathan A, Kallarakkal TG, Karen-Ng LP, Ghani WM, et al.
    Int J Med Sci, 2015;12(12):937-45.
    PMID: 26664254 DOI: 10.7150/ijms.11605
    Collagen Triple Helix Repeat Containing 1 (CTHRC1) is a protein often found to be over-expressed in various types of human cancers. However, correlation between CTHRC1 expression level with clinico-pathological characteristics and prognosis in oral cancer remains unclear. Therefore, this study aimed to determine mRNA and protein expression of CTHRC1 in oral squamous cell carcinoma (OSCC) and to evaluate the clinical and prognostic impact of CTHRC1 in OSCC.
  3. Vincent-Chong VK, Salahshourifar I, Karen-Ng LP, Siow MY, Kallarakkal TG, Ramanathan A, et al.
    ScientificWorldJournal, 2014;2014:897523.
    PMID: 25401159 DOI: 10.1155/2014/897523
    Matrix metalloproteinase 13 (MMP13) plays a central role in the MMP activation cascade that enables degradation of the extracellular matrix and basement membranes, and it is identified as a potential driver in oral carcinogenesis. Therefore, this study aims to determine the copy number, mRNA, and protein expression of MMP13 in oral squamous cell carcinoma (OSCC) and to associate these expressions with clinicopathological parameters. Copy number, mRNA, and protein expression analysis of MMP13 were determined using real-time quantitative PCR and immunohistochemistry methods in OSCC samples. The correlations between MMP13 expressions and clinicopathological parameters were evaluated, and the significance of MMP13 as a prognostic factor was determined. Despite discrepancies between gene amplification and mRNA and protein overexpression rates, OSCC cases showed high amplification of MMP13 and overexpression of MMP13 at both mRNA and protein levels. High level of MMP13 protein expression showed a significant correlation with lymph node metastasis (P = 0.011) and tumor staging (P = 0.002). Multivariate Cox regression model analysis revealed that high level of mRNA and protein expression of MMP13 were significantly associated with poor prognosis (P < 0.050). Taken together, these observations indicate that the MMP13 protein overexpression could be considered as a prognostic marker of OSCC.
  4. Vaithilingam RD, Safii SH, Baharuddin NA, Karen-Ng LP, Saub R, Ariffin F, et al.
    Oral Dis, 2015 Jan;21(1):e62-9.
    PMID: 24930489 DOI: 10.1111/odi.12267
    Periodontal bio-repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad-based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.
  5. Wong GR, Ha KO, Himratul-Aznita WH, Yang YH, Wan Mustafa WM, Yuen KM, et al.
    Oral Dis, 2014 Nov;20(8):762-7.
    PMID: 24320099 DOI: 10.1111/odi.12218
    The objective of the study was to determine the prevalence of HPV seropositivity among patients with oral squamous cell carcinoma (OSCC) and healthy individuals and to correlate the association between HPV 16 seropositivity and risk of OSCC.
  6. Siow MY, Ng LP, Vincent-Chong VK, Jamaludin M, Abraham MT, Abdul Rahman ZA, et al.
    Oral Dis, 2014 May;20(4):345-51.
    PMID: 23651447 DOI: 10.1111/odi.12118
    To identify differentially expressed miRNA between oral squamous cell carcinoma (OSCC) and non-cancer (NC) and to associate these with clinico-pathological parameters.
  7. Karen-Ng LP, Marhazlinda J, Rahman ZA, Yang YH, Jalil N, Cheong SC, et al.
    Asian Pac J Cancer Prev, 2011;12(5):1161-6.
    PMID: 21875259
    Dietary isothiocyanates (ITCs) found in cruciferous vegetables (Brassica spp.) has been reported to reduce cancer risk by inducing phase II conjugating enzymes, in particular glutathione S-transferases (GSTs). This case-control study was aimed at determining associations between dietary ITCs, GSTs polymorphisms and risk habits (cigarette smoking, alcohol drinking and betel-quid chewing) with oral cancer in 115 cases and 116 controls. Information on dietary ITC intake from cruciferous vegetables was collected via a semi-quantitative food frequency questionnaire (FFQ). Peripheral blood lymphocytes were obtained for genotyping of GSTM1, GSTT1 and GSTP1 using PCR multiplex and PCR-RFLP. Chi-square and logistic regression were performed to determine the association of ITC and GSTs polymorphism and risk of oral cancer. When dietary ITC was categorized into high (greater than/equal to median) and low (less than median) intake, there was no significant difference between cases and control group. Logistic regression yielding odd ratios resulted in no significant association between dietary ITC intake, GSTM1, GSTT1 or GSTP1 genotypes with oral cancer risk overall. However, GSTP1 wild-type genotype was associated with later disease onset in women above 55 years of age (p= 0.017). Among the men above 45 years of age, there was clinical significant difference of 17 years in the age of onset of oral cancer between GSTP1 wild-type + low ITC intake and GSTP1 polymorphism + high ITC intake (p= 0.001). Similar conditions were also seen among men above 45 years of age with risk habits like drinking and chewing as the earlier disease onset associated with GSTP1 polymorphism and high ITC intake (p< 0.001). This study suggests that combination effects between dietary ITCs, GSTP1 polymorphism and risk habits may be associated with the risk of oral cancer and modulate the age of disease onset.
  8. Vincent-Chong VK, Anwar A, Karen-Ng LP, Cheong SC, Yang YH, Pradeep PJ, et al.
    PLoS One, 2013;8(2):e54705.
    PMID: 23405089 DOI: 10.1371/journal.pone.0054705
    Despite the advances in diagnosis and treatment of oral squamous cell carcinoma (OSCC), mortality and morbidity rates have not improved over the past decade. A major drawback in diagnosis and treatment of OSCC is the lack of knowledge relating to how genetic instability in oral cancer genomes affects oral carcinogenesis. Hence, the key aim of this study was to identify copy number alterations (CNAs) that may be cancer associated in OSCC using high-resolution array comparative genomic hybridization (aCGH). To our knowledge this is the first study to use ultra-high density aCGH microarrays to profile a large number of OSCC genomes (n = 46). The most frequently amplified CNAs were located on chromosome 11q11(52%), 2p22.3(52%), 1q21.3-q22(54%), 6p21.32(59%), 20p13(61%), 7q34(52% and 72%),8p11.23-p11.22(80%), 8q11.1-q24.4(54%), 9q13-q34.3(54%), 11q23.3-q25(57%); 14q21.3-q31.1(54%); 14q31.3-q32.33(57%), 20p13-p12.3(54%) and 20q11.21-q13.33(52%). The most frequently deleted chromosome region was located on 3q26.1 (54%). In order to verify the CNAs from aCGH using quantitative polymerase chain reaction (qPCR), the three top most amplified regions and their associated genes, namely ADAM5P (8p11.23-p11.22), MGAM (7q34) and SIRPB1 (20p13.1), were selected in this study. The ADAM5P locus was found to be amplified in 39 samples and deleted in one; MGAM (24 amplifications and 3 deletions); and SIRPB1 (12 amplifications, others undetermined). On the basis of putative cancer-related annotations, two genes, namely ADAM metallopeptidase domain 9 (ADAM9) and maltase-glucoamylase alpha-glucosidase (MGAM), that mapped to CNA regions were selected for further evaluation of their mRNA expression using reverse transcriptase qPCR. The over-expression of MGAM was confirmed with a 6.6 fold increase in expression at the mRNA level whereas the fold change in ADAM9 demonstrated a 1.6 fold increase. This study has identified significant regions in the OSCC genome that were amplified and resulted in consequent over-expression of the MGAM and ADAM9 genes that may be utilized as biological markers for OSCC.
  9. Ghani WMN, Ramanathan A, Prime SS, Yang YH, Razak IA, Abdul Rahman ZA, et al.
    Cancer Invest, 2019;37(7):275-287.
    PMID: 31307249 DOI: 10.1080/07357907.2019.1635614
    Previous studies found that ethnicity influences oral cancer patients' survival; however, most studies were limited to certain ethnic groups particularly from the West, thus of limited relevance to Asians where the disease is most prevalent. We investigated the relationship between ethnicity and patient survival in multi-racial Malaysia. 5-year survival rate was 40.9%. No statistically significant difference was observed in survival between Malays, Chinese, Indians and Indigenous peoples (45.7%, 44.0%, 41.3%, 27.7% respectively). Increased tumor size, lymph node involvement and advanced tumor were predictive of poor survival. We conclude that ethnicity has no effect on survival or its prognostic indicators.
  10. Leong WY, Soon CF, Wong SC, Tee KS, Cheong SC, Gan SH, et al.
    Bioengineering (Basel), 2017 May 14;4(2).
    PMID: 28952522 DOI: 10.3390/bioengineering4020043
    Cells encapsulation is a micro-technology widely applied in cell and tissue research, tissue transplantation, and regenerative medicine. In this paper, we proposed a growth of microtissue model for the human keratinocytes (HaCaT) cell line and an oral squamous cell carcinoma (OSCC) cell line (ORL-48) based on a simple aerosol microencapsulation technique. At an extrusion rate of 20 μL/min and air flow rate of 0.3 L/min programmed in the aerosol system, HaCaT and ORL-48 cells in alginate microcapsules were encapsulated in microcapsules with a diameter ranging from 200 to 300 μm. Both cell lines were successfully grown into microtissues in the microcapsules of alginate within 16 days of culture. The microtissues were characterized by using a live/dead cell viability assay, field emission-scanning electron microscopy (FE-SEM), fluorescence staining, and cell re-plating experiments. The microtissues of both cell types were viable after being extracted from the alginate membrane using alginate lyase. However, the microtissues of HaCaT and ORL-48 demonstrated differences in both nucleus size and morphology. The microtissues with re-associated cells in spheroids are potentially useful as a cell model for pharmacological studies.
  11. Kallarakkal TG, Zaini ZM, Ghani WMN, Karen-Ng LP, Siriwardena BSMS, Cheong SC, et al.
    J Oral Pathol Med, 2024 Jan;53(1):53-60.
    PMID: 38081145 DOI: 10.1111/jop.13501
    INTRODUCTION: A major pitfall of many of the established oral epithelial dysplasia (OED) grading criteria is their lack of reproducibility and accuracy to predict malignant transformation. The main objective of this study was to determine whether calibration of practicing oral pathologists on OED grading could improve the reproducibility of the WHO 2017 and the binary OED grading systems.

    METHODS: A nationwide online exercise was carried out to determine the influence of calibration on the reproducibility of the WHO 2017 and the binary OED grading systems.

    RESULTS: A significant improvement was observed in the inter-observer agreement for the WHO 2017 OED grading system (K 0.196 vs. 0.448; Kw 0.357 vs. 0.562) after the calibration exercise. The significant difference (p = 0.027) in the level of agreement between those with five or more years and less than 5 years of experience was no more observed (p = 0.426) after the calibration exercise. The percent agreement for binary grading was significantly higher (91.8%) for buccal mucosal lesions as compared to lesions on the tongue after the calibration exercise.

    CONCLUSION: This study validates the significance of calibration in improving the reproducibility of OED grading. The nationwide exercise resulted in a statistically significant improvement in the inter-observer agreement for the WHO 2017 OED grading system among a large number of oral pathologists. It is highly recommended that similar exercises should be organized periodically by professional bodies responsible for continuing education among oral pathologists to improve the reliability of OED grading for optimal treatment of oral potentially malignant disorders.

  12. Bradley P, Deane J, O'Hara J, Kennedy M, Carrard VC, Cheong SC, et al.
    BMJ, 2024 Mar 01;384:q512.
    PMID: 38428988 DOI: 10.1136/bmj.q512
  13. Saini R, Tang TH, Zain RB, Cheong SC, Musa KI, Saini D, et al.
    J Cancer Res Clin Oncol, 2011 Feb;137(2):311-20.
    PMID: 20419384 DOI: 10.1007/s00432-010-0886-8
    PURPOSE: The purpose of this study was to evaluate the role of HPV and p53 polymorphisms in oral squamous cell carcinomas (OSCC) affecting Malaysian population.

    METHODS: We analysed frozen samples from 105 OSCC as well as 105 oral specimens derived from healthy individuals. PCR assays targeting two regions of the virus were used. PCR amplification for the analysis of p53 codon 72 arginine/proline alleles was carried out in a separate reaction.

    RESULTS: HPV DNA was detected in 51.4% OSCC samples, while 24.8% controls were found to be HPV positive. HPV was found to be significantly associated with OSCC (P 

  14. Velaithan V, Okuda KS, Ng MF, Samat N, Leong SW, Faudzi SM, et al.
    Invest New Drugs, 2017 04;35(2):250.
    PMID: 28185040 DOI: 10.1007/s10637-017-0437-0
  15. Velaithan V, Okuda KS, Ng MF, Samat N, Leong SW, Faudzi SM, et al.
    Invest New Drugs, 2017 04;35(2):166-179.
    PMID: 28058624 DOI: 10.1007/s10637-016-0423-y
    Zebrafish represents a powerful in vivo model for phenotype-based drug discovery to identify clinically relevant small molecules. By utilizing this model, we evaluated natural product derived compounds that could potentially modulate Notch signaling that is important in both zebrafish embryogenesis and pathogenic in human cancers. A total of 234 compounds were screened using zebrafish embryos and 3 were identified to be conferring phenotypic alterations similar to embryos treated with known Notch inhibitors. Subsequent secondary screens using HEK293T cells overexpressing truncated Notch1 (HEK293TΔE) identified 2 compounds, EDD3 and 3H4MB, to be potential Notch antagonists. Both compounds reduced protein expression of NOTCH1, Notch intracellular domain (NICD) and hairy and enhancer of split-1 (HES1) in HEK293TΔE and downregulated Notch target genes. Importantly, EDD3 treatment of human oral cancer cell lines demonstrated reduction of Notch target proteins and genes. EDD3 also inhibited proliferation and induced G0/G1 cell cycle arrest of ORL-150 cells through inducing p27KIP1. Our data demonstrates the utility of the zebrafish phenotypic screen and identifying EDD3 as a promising Notch antagonist for further development as a novel therapeutic agent.
  16. Prime SS, Cirillo N, Cheong SC, Prime MS, Parkinson EK
    Cancer Lett, 2021 10 10;518:102-114.
    PMID: 34139286 DOI: 10.1016/j.canlet.2021.05.025
    This study reviews the molecular landscape of oral potentially malignant disorders (OPMD). We examine the impact of tumour heterogeneity, the spectrum of driver mutations (TP53, CDKN2A, TERT, NOTCH1, AJUBA, PIK3CA, CASP8) and gene transcription on tumour progression. We comment on how some of these mutations impact cellular senescence, field cancerization and cancer stem cells. We propose that OPMD can be monitored more closely and more dynamically through the use of liquid biopsies using an appropriate biomarker of transformation. We describe new gene interactions through the use of a systems biology approach and we highlight some of the first studies to identify functional genes using CRISPR-Cas9 technology. We believe that this information has translational implications for the use of re-purposed existing drugs and/or new drug development. Further, we argue that the use of digital technology encompassing clinical and laboratory-based data will create relevant datasets for machine learning/artificial intelligence. We believe that therapeutic intervention at an early molecular premalignant stage should be an important preventative strategy to inhibit the development of oral squamous cell carcinoma and that this approach is applicable to other aerodigestive tract cancers.
  17. Vaithilingam RD, Safii SH, Baharuddin NA, Ng CC, Cheong SC, Bartold PM, et al.
    J Periodontal Res, 2014 Dec;49(6):683-95.
    PMID: 24528298 DOI: 10.1111/jre.12167
    Studies to elucidate the role of genetics as a risk factor for periodontal disease have gone through various phases. In the majority of cases, the initial 'hypothesis-dependent' candidate-gene polymorphism studies did not report valid genetic risk loci. Following a large-scale replication study, these initially positive results are believed to be caused by type 1 errors. However, susceptibility genes, such as CDKN2BAS (Cyclin Dependend KiNase 2B AntiSense RNA; alias ANRIL [ANtisense Rna In the Ink locus]), glycosyltransferase 6 domain containing 1 (GLT6D1) and cyclooxygenase 2 (COX2), have been reported as conclusive risk loci of periodontitis. The search for genetic risk factors accelerated with the advent of 'hypothesis-free' genome-wide association studies (GWAS). However, despite many different GWAS being performed for almost all human diseases, only three GWAS on periodontitis have been published - one reported genome-wide association of GLT6D1 with aggressive periodontitis (a severe phenotype of periodontitis), whereas the remaining two, which were performed on patients with chronic periodontitis, were not able to find significant associations. This review discusses the problems faced and the lessons learned from the search for genetic risk variants of periodontitis. Current and future strategies for identifying genetic variance in periodontitis, and the importance of planning a well-designed genetic study with large and sufficiently powered case-control samples of severe phenotypes, are also discussed.
  18. Chai SJ, Yap YY, Foo YC, Yap LF, Ponniah S, Teo SH, et al.
    PLoS One, 2015;10(11):e0130464.
    PMID: 26536470 DOI: 10.1371/journal.pone.0130464
    Nasopharyngeal carcinoma (NPC) is highly prevalent in South East Asia and China. The poor outcome is due to late presentation, recurrence, distant metastasis and limited therapeutic options. For improved treatment outcome, immunotherapeutic approaches focusing on dendritic and autologous cytotoxic T-cell based therapies have been developed, but cost and infrastructure remain barriers for implementing these in low-resource settings. As our prior observations had found that four-jointed box 1 (FJX1), a tumor antigen, is overexpressed in NPCs, we investigated if short 9-20 amino acid sequence specific peptides matching to FJX1 requiring only intramuscular immunization to train host immune systems would be a better treatment option for this disease. Thus, we designed 8 FJX1-specific peptides and implemented an assay system to first, assess the binding of these peptides to HLA-A2 molecules on T2 cells. After, ELISPOT assays were used to determine the peptides immunogenicity and ability to induce potential cytotoxicity activity towards cancer cells. Also, T-cell proliferation assay was used to evaluate the potential of MHC class II peptides to stimulate the expansion of isolated T-cells. Our results demonstrate that these peptides are immunogenic and peptide stimulated T-cells were able to induce peptide-specific cytolytic activity specifically against FJX1-expressing cancer cells. In addition, we demonstrated that the MHC class II peptides were capable of inducing T-cell proliferation. Our results suggest that these peptides are capable of inducing specific cytotoxic cytokines secretion against FJX1-expressing cancer cells and serve as a potential vaccine-based therapy for NPC patients.
  19. Chai SJ, Fong SCY, Gan CP, Pua KC, Lim PVH, Lau SH, et al.
    Hum Vaccin Immunother, 2019;15(1):167-178.
    PMID: 30193086 DOI: 10.1080/21645515.2018.1520584
    Peptide vaccines derived from tumour-associated antigens have been used as an immunotherapeutic approach to induce specific cytotoxic immune response against tumour. We previously identified that MAGED4B and FJX1 proteins are overexpressed in HNSCC patients; and further demonstrated that two HLA-A2-restricted 9-11 amino acid peptides derived from these proteins were able to induce anti-tumour immune responses in vitro independently using PBMCs isolated from these patients. In this study, we evaluated the immunogenicity and efficacy of a dual-antigenic peptide vaccine (PV1), comprised of MAGED4B and FJX1 peptides in HNSCC patients. We first demonstrated that 94.8% of HNSCC patients expressed MAGED4B and/or FJX1 by immunohistochemistry, suggesting that PV1 could benefit the majority of HNSCC patients. The presence of pre-existing MAGED4B and FJX1-specific T-cells was detected using a HLA-A2 dimer assay and efficacy of PV1 to induce T-cell to secrete cytotoxic cytokine was evaluated using ELISPOT assay. Pre-existing PV1-specific T-cells were detected in all patients. Notably, we demonstrated that patients' T-cells were able to secrete cytotoxic cytokines upon exposure to target cells expressing the respective antigen post PV1 stimulation. Furthermore, patients with high expression of MAGED4B and FJX1 in their tumours were more responsive to PV1 stimulation, demonstrating the specificity of the PV1 peptide vaccine. Additionally, we also demonstrated the expression of MAGED4B and FJX1 in breast, lung, colon, prostate and rectal cancer suggesting the potential use of PV1 in these cancers. In summary, PV1 could be a good vaccine candidate for the treatment of HNSCC patients and other cancers expressing these antigens.
  20. Wang C, Zainal NS, Chai SJ, Dickie J, Gan CP, Zulaziz N, et al.
    Front Immunol, 2021;12:763086.
    PMID: 34733290 DOI: 10.3389/fimmu.2021.763086
    HPV-independent head and neck squamous cell carcinoma (HNSCC) is a common cancer globally. The overall response rate to anti-PD1 checkpoint inhibitors (CPIs) in HNSCC is ~16%. One major factor influencing the effectiveness of CPI is the level of tumor infiltrating T cells (TILs). Converting TILlow tumors to TILhigh tumors is thus critical to improve clinical outcome. Here we describe a novel DNA vaccines to facilitate the T-cell infiltration and control tumor growth. We evaluated the expression of target antigens and their respective immunogenicity in HNSCC patients. The efficacy of DNA vaccines targeting two novel antigens were evaluated with or without CPI using a syngeneic model. Most HNSCC patients (43/44) co-expressed MAGED4B and FJX1 and their respective tetramer-specific T cells were in the range of 0.06-0.12%. In a preclinical model, antigen-specific T cells were induced by DNA vaccines and increased T cell infiltration into the tumor, but not MDSC or regulatory T cells. The vaccines inhibited tumor growth and improved the outcome alone and upon combination with anti-PD1 and resulted in tumor clearance in approximately 75% of mice. Pre-existence of MAGED4B and FJX1-reactive T cells in HNSCC patients suggests that these widely expressed antigens are highly immunogenic and could be further expanded by vaccination. The DNA vaccines targeting these antigens induced robust T cell responses and with the anti-PD1 antibody conferring excellent tumor control. This opens up an opportunity for combination immunotherapy that might benefit a wider population of HNSCC patients in an antigen-specific manner.
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