Displaying publications 1 - 20 of 36 in total

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  1. Chan SW, Kallarakkal TG, Abraham MT
    Asian Pac J Cancer Prev, 2014;15(5):2145-52.
    PMID: 24716948
    BACKGROUND: The survival rate for oral squamous cell carcinoma (OSCC) has remained generally unchanged in the past three decades, underlining the need for more biomarkers to be developed to aid prognostication and effective management. The prognostic potential of E-cadherin expression in OSCCs has been variable in previous studies while galectin-9 expression has been correlated with improved prognosis in other cancers. The aim of the present study was to investigate the expression of galectin-9 and E-cadherin in OSCC and their potential as prognostic biomarkers.

    MATERIALS AND METHODS: E-cadherin and Galectin-9 expression was examined by immunohistochemistry in 32 cases of OSCC of the buccal mucosa (13 with and 19 without lymph node metastasis), as well as 6 samples of reactive lesions and 5 of normal buccal mucosa.

    RESULTS: The expression of E-cadherin in OSCC was significantly lower than the control tissues but galectin-9 expression was conversely higher. Median E-cadherin HSCOREs between OSCCs positive and negative for nodal metastasis were not significantly different. Mean HSCOREs for galectin-9 in OSCC without lymph node metastasis (127.7 ± 81.8) was higher than OSCC with lymph node metastasis (97.9 ± 62.9) but this difference was not statistically significant.

    CONCLUSIONS: E-cadherin expression is reduced whilst galectin-9 expression is increased in OSCC. However, the present results suggest that E-cadherin and galectin-9 expression may not be useful as prognostic markers for OSCC.

  2. Kallarakkal TG, Ramanathan A, Zain RB
    Int J Dent, 2013;2013:298249.
    PMID: 24223590 DOI: 10.1155/2013/298249
    Verrucous papillary lesions (VPLs) of oral cavity are diagnostically challenging as they include a spectrum of benign, potentially malignant, and frankly malignant lesions. A majority of the benign VPLs have viral aetiology and include commonly occurring squamous papilloma along with verruca vulgaris, focal epithelial hyperplasia, and condyloma. Current understanding of potentially malignant VPLs is perplexing and is primarily attributed to the use of confusing and unsatisfactory terminology. Clinically and histologically oral verrucous hyperplasia, a potentially malignant disorder, resembles oral verrucous carcinoma and may be indistinguishable from one another. The most reliable way to separate these entities on routine haematoxylin-eosin stained tissue sections is to recognize the exophytic growth patterns of oral verrucous hyperplasia from the combined exophytic and endophytic growth patterns associated with verrucous carcinoma. A review of the literature showed that there is a lot of confusion regarding the current clinical and histopathological guidelines to diagnose this potentially malignant entity. The criteria elaborated by different authors in establishing the diagnosis of oral verrucous hyperplasia are discussed in detail. A brief overview of the treatment modalities adopted is also discussed. The need for establishing a clear understanding of this potentially malignant entity is stressed as it may have far reaching implications on its management.
  3. Abdelrahim LM, Peh SC, Kallarakkal TG
    Malays J Pathol, 2018 Apr;40(1):49-56.
    PMID: 29704384
    INTRODUCTION: Epstein-Barr virus (EBV) might be an aetiological agent involved in the pathogenesis of certain Non-Hodgkin's Lymphomas (NHLs). EBV infection has been diagnosed by serologic testing within the tumour biopsies of patients with NHL. However, the association between EBV and NHL is inconsistent with a preference for certain anatomic sites, histologic subtypes and immunosuppressed patients. The objective of this study was to characterise the B-cell NHLs of the oral cavity and maxillofacial region using histological and immunophenotypical techniques and to determine its association with EBV infection.

    MATERIALS AND METHODS: This was a descriptive cross-sectional study that included 14 cases of B-cell NHLs of the oral cavity and maxillofacial region. The haematopoietic and lymphoid tissue tumours classification of WHO was used to categorize the cases. In-situ hybridisation for EBV-encoded RNA was performed to confirm the EBV infection.

    RESULTS: The average age of the patients included in the study was found to be 48.8 ± 23 years with a higher female to male ratio (1.3:1). Our study suggested that diffuse large B-cell lymphomas (DLBCLs) and Burkitt's lymphomas (BLs) constitute the predominant subtypes of lymphomas affecting the oral cavity and maxillofacial regions.

    CONCLUSION: The findings from our study support the view that at least a relatively smaller proportion of B-cell NHLs that occur in the oral cavity and maxillofacial region do not have a pathogenic association with EBV.

  4. Salahshourifar I, Vincent-Chong VK, Kallarakkal TG, Zain RB
    Oral Oncol, 2014 May;50(5):404-12.
    PMID: 24613650 DOI: 10.1016/j.oraloncology.2014.02.005
    Oral cancer is a multifactorial disease in which both environmental and genetic factors contribute to the aetiopathogenesis. Oral cancer is the sixth most common cancer worldwide with a higher incidence among Melanesian and South Asian countries. More than 90% of oral cancers are oral squamous cell carcinoma (OSCC). The present study aimed to determine common genomic copy number alterations (CNAs) and their frequency by including 12 studies that have been conducted on OSCCs using array comparative genomic hybridization (aCGH). In addition, we reviewed the literature dealing with CNAs that drive oral precursor lesions to the invasive tumors. Results showed a sequential accumulation of genetic changes from oral precursor lesions to invasive tumors. With the disease progression, accumulation of genetic changes increases in terms of frequency, type and size of the abnormalities, even on different regions of the same chromosome. Gains in 3q (36.5%), 5p (23%), 7p (21%), 8q (47%), 11q (45%), 20q (31%) and losses in 3p (37%), 8p (18%), 9p (10%) and 18q (11%) were the most common observations among those studies. However, losses are less frequent than gains but it appears that they might be the primary clonal events in causing oral cancer.
  5. Tegginamani AS, Kallarakkal TG, Vanishree HS, Muttalib KBA
    J Coll Physicians Surg Pak, 2019 Jul;29(7):688.
    PMID: 31253228 DOI: 10.29271/jcpsp.2019.07.688
  6. Chang SW, Kareem SA, Kallarakkal TG, Merican AF, Abraham MT, Zain RB
    Asian Pac J Cancer Prev, 2011;12(10):2659-64.
    PMID: 22320970
    The incidence of oral cancer is high for those of Indian ethnic origin in Malaysia. Various clinical and pathological data are usually used in oral cancer prognosis. However, due to time, cost and tissue limitations, the number of prognosis variables need to be reduced. In this research, we demonstrated the use of feature selection methods to select a subset of variables that is highly predictive of oral cancer prognosis. The objective is to reduce the number of input variables, thus to identify the key clinicopathologic (input) variables of oral cancer prognosis based on the data collected in the Malaysian scenario. Two feature selection methods, genetic algorithm (wrapper approach) and Pearson's correlation coefficient (filter approach) were implemented and compared with single-input models and a full-input model. The results showed that the reduced models with feature selection method are able to produce more accurate prognosis results than the full-input model and single-input model, with the Pearson's correlation coefficient achieving the most promising results.
  7. Chan SW, Liew LH, Wong GR, Kallarakkal TG, Abraham MT, Ramanathan A, et al.
    Int. J. Surg. Pathol., 2016 Aug;24(5):401-9.
    PMID: 27006298 DOI: 10.1177/1066896916639372
    BACKGROUND: Turnaround time (TAT) is the benchmark to assess the performance of a laboratory, pathologists, and pathology services, but there are few articles on TAT of surgical pathology, particularly in relation to oral or head and neck specimens. This study investigates the TAT for oral histopathology reporting in an academic institution's training laboratory and offers recommendations to achieve better overall quality of diagnostic services.

    METHODS: This study examined data obtained from biopsy request forms for specimens received from the Oro-Maxillofacial Surgery Department of Hospital Tengku Ampuan Rahimah Klang in the Oral Pathology Diagnostic Laboratory of the Faculty of Dentistry, University of Malaya, over a period of 3 years between January 2012 and October 2014.

    RESULTS: TAT for surgical and decalcified specimens were increased significantly compared to biopsies. Additional special handling did not influence TAT, but increased specimen volume resulted in greater TAT. Slide interpretation was the most time-consuming stage during histopathology reporting. Overall, mean TAT was acceptable for most specimens, but the TAT goals were less than satisfactory.

    CONCLUSION: A TAT goal appropriate for this laboratory may hence be established based on this study. Collective efforts to improve the TAT for various specimens are essential for better laboratory performance in the future.
  8. Tegginamani AS, Shivakumar VH, Kallarakkal TG, Ismail SM, Abraham MT, Bin Zamzuri AT
    J Oral Maxillofac Pathol, 2020 09 09;24(2):400.
    PMID: 33456258 DOI: 10.4103/jomfp.JOMFP_272_19
    Background: Oral potentially malignant disorders have a risk for malignant transformation but are difficult to reliably identify and predict which patients are at the risk for malignant transformation. OCT4 has been hypothesized to play a key oncogenic driver in a variety of solid tumors. A deeper understanding of the aberrant molecular pathways which lead to carcinogenesis needs to be identified by the potential markers.

    Aims: To assess the OCT4 stemness factor in oral leukoplakia for its potential risk to malignant transformation.

    Settings and Design: 20 cases of oral leukoplakia were obtained from archives at Oral Cancer Research & Coordinating center (OCRCC) Malaysia Subjects and Methods: 20 cases of oral leukoplakia were assessed by OCT4 immunohistochemically. Oral squamous cell carcinoma was used as a control.

    Result: no expression of OCT 4 was observed in any cases of oral leukoplakia.

    Conclusion: The molecular mechanisms of Oct4 regulation and in particular of its switch on and off in tissues depends upon its microenvironment, which makes it challenging in fundamental and applied research fields of regenerative medicine and cancer therapy. It's better that patients should undergo multiple biopsies for the early detection of malignant transformation with close follow-up during the first two to three years, a large amount of work remains to be done with multi-marker panel investigation, as cure rates have remained constant over three decades.

  9. Kazakydasan S, Rahman ZA, Ismail SM, Abraham MT, Kallarakkal TG
    J Oral Pathol Med, 2016 Jul 15.
    PMID: 27417330 DOI: 10.1111/jop.12476
    Lymph node metastasis in oral squamous cell carcinoma (OSCC) is a well-known independent prognostic factor. However, the identification of occult tumour cells within the lymph nodes has remained a challenge for the pathologist as well as the clinician.
  10. Govindaraj PK, Kallarakkal TG, Mohd Zain R, Tilakaratne WM, Lew HL
    PLoS One, 2021;16(12):e0261575.
    PMID: 34941961 DOI: 10.1371/journal.pone.0261575
    BACKGROUND: Local relapse of oral squamous cell carcinoma in non-involved mucosal surgical margins indicated possibility of field alteration in the margins, which could be predicted with certain biomarkers. The objectives were to evaluate the expression of Ki-67, Cornulin and ISG15 in non-involved mucosal surgical margins and the association of clinicopathological prognosticators with local relapse in oral squamous cell carcinoma.

    METHODS: Surgical margins from the study (relapse) group (n = 23), control (non-relapse) group (n = 32) and normal oral mucosa (n = 5) were immunohistochemically stained using Ki-67, Cornulin and ISG15 antibodies. Association between expression of markers and clinicopathological prognosticators with local relapse in oral squamous cell carcinoma was analyzed statistically.

    RESULTS: The study group surgical margins demonstrated significantly decreased Cornulin expression (p = 0.032). Low Cornulin expression was significantly associated with local relapse (p = 0.004) and non-tongue primary tumor (p = 0.013). Although not significantly associated with local relapse, expression of Ki-67 was significantly reduced in female patients (p = 0.041). Age above 57.5 years, Chinese & Indian ethnicity, alcohol consumption, epithelial dysplasia in surgical margins, and type III and IV patterns of invasion of tumor were also significantly related to local relapse. Regression analysis showed low expression of Cornulin (p = 0.018), and increased patient's age (p = 0.008) were predictors of local relapse in oral squamous cell carcinoma, with 34-fold risk and 18-fold risk, respectively. Expression of Ki-67 and ISG15 did not show significant association with local relapse in oral squamous cell carcinoma.

    CONCLUSION: Low expression of Cornulin is an independent predictor of relapse in oral squamous cell carcinoma.

  11. Burhanudin NA, Zaini ZM, Rahman ZAA, Ismail SM, Gopinath D, Abraham MT, et al.
    PMID: 36229363 DOI: 10.1016/j.oooo.2022.07.014
    OBJECTIVE: Extranodal extension (ENE) is an important prognostic factor in oral squamous cell carcinoma (OSCC). However, ENE is only confirmed postoperatively by histologic assessment of the lymph nodes after neck dissection. Accurate identification of ENE preoperatively would help in management of OSCC.

    STUDY DESIGN: We determined the expression of molecular markers gamma glutamyl hydrolase (GGH), cyclin-dependent kinase inhibitor-3 (CDKN3), and chromobox homolog-7 (CBX7) using immunohistochemistry in OSCC clinical samples (n = 35). The intensity of staining was scored using a semiquantitative index (HSCORE). The association between clinicopathologic parameters and expression of molecular markers with ENE status was analyzed using chi-square test.

    RESULTS: The number of positive nodes and the highest anatomic level of nodal involvement significantly correlated with ENE (P < .05). High GGH expression was significantly associated with ENE (P < .05), with an increased risk for ENE (odds ratio [OR] 9.9, 95% CI 1.08-91.47, P = .04), whereas no significant association was seen for CDKN3 and CBX7 expression with ENE. However, a trend toward significance was observed with a high level of CDKN3 and a low level of CBX7 expression with ENE.

    CONCLUSIONS: Gamma glutamyl hydrolase offers potential as a predictor for ENE in OSCC, whereas the role of CDKN3 and CBX7 need to be validated in a larger sample.

  12. Haron N, Zain RB, Nabillah WM, Saleh A, Kallarakkal TG, Ramanathan A, et al.
    Telemed J E Health, 2017 03;23(3):192-199.
    PMID: 27541205 DOI: 10.1089/tmj.2016.0128
    INTRODUCTION: This study examined the concordance in clinical diagnosis of high-risk lesions in the oral cavity and referral decisions between clinical oral examination (COE) and teledentistry.

    MATERIALS AND METHODS: Sixteen individuals with a range of oral potentially malignant disorders (OPMD) and normal oral mucosa were included. Five areas of the oral cavity were photographed by three dentists using mobile phone cameras with 5 MP-13 MP resolutions. On the same day, the patients were given COE by two oral medicine specialists (OMS) and 3 weeks later, they reviewed the images taken using the phone, and concordance was examined between the two by Kappa statistics. The sensitivity and specificity of clinical diagnosis using the phone images were also measured. Pre- and post-program questionnaires were answered by both the dentists and the OMS to determine the feasibility of integrating teledentistry in their clinical practice.

    RESULTS: The Kappa values in determining the presence of lesion, category of lesion (OPMD or not), and making referral decision were moderate to strong (0.64-1.00). The overall sensitivity was more than 70% and specificity was 100%. The false negative rate decreased as the camera resolution increased. All dentists agreed that the process could facilitate early detection of oral mucosal lesion, and was easy to use in the clinic.

    CONCLUSIONS: This study provides evidence that teledentistry can be used for communication between primary care and OMS and could be readily integrated into clinical setting for patient management.

  13. 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.

  14. Yong ZW, Zaini ZM, Kallarakkal TG, Karen-Ng LP, Rahman ZA, Ismail SM, et al.
    Sci Rep, 2014;4:6073.
    PMID: 25123227 DOI: 10.1038/srep06073
    The clinical relevance of DNA copy number alterations in chromosome 8 were investigated in oral cancers. The copy numbers of 30 selected genes in 33 OSCC patients were detected using the multiplex ligation-dependent probe amplification (MLPA) technique. Amplifications of the EIF3E gene were found in 27.3% of the patients, MYC in 18.2%, RECQL4 in 15.2% and MYBL1 in 12.1% of patients. The most frequent gene losses found were the GATA4 gene (24.2%), FGFR1 gene (24.2%), MSRA (21.2) and CSGALNACT1 (12.1%). The co-amplification of EIF3E and RECQL4 was found in 9% of patients and showed significant association with alcohol drinkers. There was a significant association between the amplification of EIF3E gene with non-betel quid chewers and the negative lymph node status. EIF3E amplifications did not show prognostic significance on survival. Our results suggest that EIF3E may have a role in the carcinogenesis of OSCC in non-betel quid chewers.
  15. 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.
  16. Auzair LB, Vincent-Chong VK, Ghani WM, Kallarakkal TG, Ramanathan A, Lee CE, et al.
    Eur Arch Otorhinolaryngol, 2016 Jul;273(7):1885-93.
    PMID: 26138391 DOI: 10.1007/s00405-015-3703-9
    Caveolin-1 (Cav-1) and Actin-Related Protein 2/3 Complex, Subunit 1B (ARPC1B) have been implicated in various human cancers, yet its role in tumorigenesis remains controversial. Therefore, this study aims to determine the protein expression of these two genes in oral squamous cell carcinomas (OSCCs) and to evaluate the clinical and prognostic impact of these genes in OSCC. Protein expressions of these two genes were determined by immunohistochemistry technique. The association between Cav-1 and ARPC1B with clinico-pathological parameters was evaluated by Chi-square test (or Fisher exact test where appropriate). Correlation between the protein expressions of these 2 genes with survival was analyzed using Kaplan-Meier and Cox regression models. Cav-1 and ARPC1B were found to be significantly over-expressed in OSCC compared to normal oral mucosa (p = 0.002 and p = 0.033, respectively). Low level of ARPC1B protein expression showed a significant correlation with lymph node metastasis (LNM) (p = 0.010) and advanced tumor staging (p = 0.003). Kaplan-Meier survival analyses demonstrated that patients with over-expression of Cav-1 protein were associated with poor prognosis (p = 0.030). Adjusted multivariate Cox regression model revealed that over-expression of Cav-1 remained as an independent significant prognostic factor for OSCC (HRR = 2.700, 95 % CI 1.013-7.198, p = 0.047). This study demonstrated that low-expression of ARPC1B is significantly associated with LNM and advanced tumor staging whereas high expression of Cav-1 can be a prognostic indicator for poor prognosis in OSCC patients.
  17. Kong YH, Syed Zanaruddin SN, Lau SH, Ramanathan A, Kallarakkal TG, Vincent-Chong VK, et al.
    PLoS One, 2015;10(7):e0134045.
    PMID: 26214683 DOI: 10.1371/journal.pone.0134045
    Oral squamous cell carcinoma (OSCC) is an aggressive disease accounting for more than 260,000 cancer cases diagnosed and 128,000 deaths worldwide. A large majority of cancer deaths result from cancers that have metastasized beyond the primary tumor. The relationship between genetic changes and clinical outcome can reflect the biological events that promote cancer's aggressive behavior, and these can serve as molecular markers for improved patient management and survival. To this end, epithelial-mesenchymal transition (EMT) is a major process that promotes tumor invasion and metastasis, making EMT-related proteins attractive diagnostic biomarkers and therapeutic targets. In this study, we used immunohistochemistry to study the expression of a panel of transcription factors (TWIST1, SNAI1/2, ZEB1 and ZEB2) and other genes intimately related to EMT (CDH1 and LAMC2) at the invasive tumor front of OSCC tissues. The association between the expression of these proteins and clinico-pathological parameters were examined with Pearson Chi-square and correlation with survival was analyzed using Kaplan Meier analysis. Our results demonstrate that there was a significant differential expression of CDH1, LAMC2, SNAI1/2 and TWIST1 between OSCC and normal oral mucosa (NOM). Specifically, CDH1 loss was significantly associated with Broder's grading, while diffused LAMC2 was similarly associated with non-cohesive pattern of invasion. Notably, co-expression of TWIST1 and ZEB2 in OSCC was significantly associated with poorer overall survival, particularly in patients without detectable lymph node metastasis. This study demonstrates that EMT-related proteins are differentially expressed in OSCC and that the co-expression of TWIST1 and ZEB2 could be of clinical value in identifying patients with poor survival for appropriate patient management.
  18. Zain RB, Pateel DGS, Ramanathan A, Kallarakkal TG, Wong GR, Yang YH, et al.
    J Cancer Educ, 2020 Aug 21.
    PMID: 32821988 DOI: 10.1007/s13187-020-01814-1
    Early diagnosis of oral cancer results in less aggressive treatment and improves the quality of life and overall 5-year survival rate. Well-trained dental professionals can play a crucial role in the early detection of oral cancers. The present study aims to determine the effectiveness of the training program "OralDETECT", a spaced repetitive, test-enhanced learning tool with a corrective feedback mechanism for early detection of oral cancer. Thirty-two dentists and 259 dental students from three Malaysian dental schools were involved in this study. All participants were trained and calibrated to recognize oral potentially malignant disorders (OPMD) and oral cancer using "OralDETECT", which is comprised of a series of pre-test, lecture, post-tests and review sessions. The percentage of correct answers (scores) for each test given by the participants was calculated and analysed using a paired t test. It was found that the overall percentage of diagnostic accuracy for both dental professionals and student groups increased to above 80% from the pre-tests to the final post-tests. There was a significant improvement in overall scores between the pre-tests and all three post-tests for the dental professional groups and the student groups. The diagnostic accuracy for individual OPMD and lesions suspicious of oral cancer also increased to above 80% for both groups. The results of our study demonstrate that the "OralDETECT" is an efficient and effective competency tool which can be used to train dental professionals and students for the early detection of OPMD and oral cancer.
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