Displaying publications 1 - 20 of 109 in total

Abstract:
Sort:
  1. Fulltext p63 as a complimentary basal cell specific marker to high molecular weight-cytokeratin in distinguishing prostatic carcinoma from benign prostatic lesions
    Shiran MS, Tan GC, Sabariah AR, Rampal L, Phang KS
    Med J Malaysia, 2007 Mar;62(1):36-9.
    PMID: 17682568 MyJurnal
    The diagnosis of prostatic carcinoma (Pca) on routine biopsies may be challenging, and to date the commonly used marker to distinguish prostate carcinoma from benign prostatic lesions has been High Molecular Weight-Cytokeratin (HMW-CK). However, the antigen of HMW-CK is susceptible to the effect of formalin fixation and causes frequent loss or patchy staining in the obviously benign glands. More recently, antibodies to p63 have been reported to be more sensitive than HMW-CK for the detection of prostatic basal cells. p63, a homologue of tumour suppressor gene p53, is essential for prostate development and is selectively expressed in the nuclei of basal cells of normal prostate glands. The objective of this study is to compare the sensitivity and specificity of HMW-CK and p63 in distinguishing prostatic carcinomas from benign prostatic lesions, as well as determining their positive predictive values. Seventy-two cases from HUKM (comprising 29 prostatic carcinomas and 43 benign prostatic hyperplasias) were stained for both HMW-CK and p63. The sensitivity of p63 and HMW-CK in identifying basal cells in benign glands was 88.37% and 90.70% respectively. The specificity of both reagents was 100%, and the positive predictive value for both reagents was also 100%. Thus, p63 is a useful complementary basal cell specific stain to HMW-CK, and would be very helpful to practicing pathologists in dealing with difficult cases.
  2. Xanthomatous meningioma: A metaplastic or degenerative phenomenon?
    Wong YP, Tan GC, Kumar R
    Neuropathology, 2018 Dec;38(6):619-623.
    PMID: 30187570 DOI: 10.1111/neup.12511
    Xanthomatous changes can be observed in various conditions including primary xanthomatosis that is linked to an underlying hypercholesterolemia and more commonly associated with secondary xanthomatous degenerative processes in neoplasm and chronic inflammation. Meningioma with extensive xanthomatous change is exceedingly rare. The presence of cholesterol clefts within this peculiar meningioma subtype has not been described. Herein, we report an unusual case of xanthomatous meningioma in an 83-year-old normolipidemic woman, who presented to us with worsening lower limb weakness and global aphasia. There was increasing evidence to suggest that the presence of xanthomatous changes in long-standing meningioma is merely a sequela of cellular degeneration rather than true metaplastic change as previously hypothesized. Hence, the diagnosis of "xanthomatous meningioma" in the metaplastic category should be revisited and considered as a distinct histological subtype. The possible histogenesis of such intriguing phenomenon is discussed with a review of the literature.
  3. Virtual meeting in pathology: Time to adapt to the new-norm
    Wong YP, Tan GC
    Malays J Pathol, 2021 Apr;43(1):1.
    PMID: 33903298
    No abstract available.
  4. Fulltext Vascular endothelial growth factor expression in placenta of hypertensive disorder in pregnancy
    Azliana AF, Zainul-Rashid MR, Chandramaya SF, Farouk WI, Nurwardah A, Wong YP, et al.
    Indian J Pathol Microbiol, 2018 1 13;60(4):515-520.
    PMID: 29323064 DOI: 10.4103/IJPM.IJPM_376_16
    INTRODUCTION: Hypertensive disorder in pregnancy (HDP) represents the most common medical complication in pregnancy. It is the leading cause of maternal and perinatal mortality and morbidity. Vascular endothelial growth factor (VEGF) stimulates vascular endothelial cell growth, survival, and proliferation, and they are known to be expressed in human placenta. The aim of this study was to determine the VEGF expression in the placenta of hypertensive and normotensive patients.

    MATERIALS AND METHODS: This is a retrospective, cross-sectional study from January 1, 2015 to December 31, 2015. A total of 30 placentae comprised of 15 hypertensive and 15 normotensive cases were assessed. VEGF expression in placenta was assessed by immunohistochemistry, and the number of syncytial knots was counted.

    RESULTS: Our study showed an increased syncytial knot formation in the placenta of hypertensive mothers. VEGF expression was seen in syncytiotrophoblasts of 14 of the hypertensive cases (14/15, 93.3%), while only two of the normotensive cases were positive (2/15, 13.3%). There were no statistically significant differences in VEGF expression in other placenta cells, that is, cytotrophoblasts (P = 1.0), decidual cells (0.1394), maternal endothelial cells (0.5977), and fetal endothelial cells (P = 1.0).

    CONCLUSIONS: This study showed an increased number of syncytial knots is a consistent histological finding in the placenta of patient with HDP. VEGF expression was significantly increased in syncytiotrophoblasts in placenta of hypertensive group, and it could be used as a biomarker for hypertension.

  5. Value of human amniotic epithelial cells in tissue engineering for cornea
    Fatimah SS, Ng SL, Chua KH, Hayati AR, Tan AE, Tan GC
    Hum. Cell, 2010 Nov;23(4):141-51.
    PMID: 21166885 DOI: 10.1111/j.1749-0774.2010.00096.x
    Human amniotic epithelial cells (hAECs) are potentially one of the key players in tissue engineering due to their easy availability. The aim of the present study was to develop an optimal isolation and transportation technique, as well as to determine the immunophenotype and epithelial gene expression of hAECs. Amnion was mechanically peeled off from the chorion and digested with trypsin-ethylenediaminetetraacetic acid. The isolated hAECs were cultured in medium containing 10 ng/mL epidermal growth factor until P4. The epithelial gene expression, cell surface antigen and protein expression of hAECs were analyzed by quantitative polymerase chain reaction, flow cytometry and immunocytochemistry. hAECs were also cultured in adipogenic, osteogenic and neurogenic induction media. The best cell yield of hAECs was seen in the digestion of 15 pieces of amnion (2 × 2 cm) and isolated 30 min after digestion with trypsin. F12:Dulbecco's modified eagle medium was the best medium for short term storage at 4 °C. hAECs expressed CD9, CD44, CD73 and CD90, and negligibly expressed CD31, CD34, CD45 and CD117. After serial passage, CK3, CK19 and involucrin gene expressions were upregulated, while p63, CK1 and CK14 gene expressions were downregulated. Sustained gene expressions of integrin β1 and CK18 were observed. At initial culture, these cells might have stem-like properties. However, they differentiated after serial passage. Nonetheless, hAECs have epithelial stem cell characteristics and have the potential to differentiate into corneal epithelial cells. Further investigations are still needed to elucidate the mechanism of differentiation involved and to optimize the culture condition for long term in vitro culture.
  6. Fulltext Utility of Ki-67 and p53 in distinguishing cervical intraepithelial neoplasia 3 from squamous cell carcinoma of the cervix
    Tan GC, Sharifah NA, Shiran MS, Salwati S, Hatta AZ, Paul-Ng HO
    Asian Pac J Cancer Prev, 2008 Oct-Dec;9(4):781-4.
    PMID: 19256776
    The differentiation between cervical intraepithelial neoplasia 3 (CIN 3) and early squamous cell carcinoma (SCC) of the cervix may be difficult in certain situations. Identification of invasion beyond the basement membrane is the gold standard for the diagnosis of the latter. The objective of this study was to determine whether the use of Ki-67 and p53 could help in solving the above dilemma. This was a retrospective study on 61 cases of cervical neoplasms comprising of 25 cases of CIN 3 and 36 SCC. All cases were evaluated by immunohistochemistry using Ki-67 and p53 monoclonal antibodies. Results showed that the differences of Ki-67 and p53 expression between CIN 3 and SCC were statistically significant. In conclusion, Ki-67 and p53 may serve as helpful adjuncts to routinely-stained histological sections in differentiating between CIN 3 and SCC.
  7. Upregulation of SOX-2, FZD9, Nestin, OCT-4 and FGF-4 expression in human chorion derived-stem cells after angiogenic induction
    Abdul Rahman H, Manzor NF, Tan GC, Tan AE, Chua KH
    Med J Malaysia, 2008 Jul;63 Suppl A:57-8.
    PMID: 19024982
    Angiogenic induction was made to promote angiogenesis by differentiating stem cells towards endothelial cells. However, the stemness property of induced cells has not been revealed yet. Hence, we aim to evaluate the differential mRNA expression of stemness genes in human chorion-derived stem cells (CDSC) after being cultured in EDM50 comprised bFGF and VEGF. Results indicated that CDSC cultured in EMD50 expressed significantly higher mRNA level of Sox-2, FZD9, BST-1 and Nestin. In addition Oct-4, FGF-4 and ABCG-2 were also upregulated. Our finding suggested that CDSC after angiogenic induction enhanced its stem cell properties. This could be contributed for the mechanism of stem cell therapy in ischemic problem.
  8. Unusual form of superficial spreading microinvasive squamous cell carcinoma of uterine cervix involving the endometrium of uterus
    Tan GC, Isa MR, Ng SP, Jamil YM
    J Obstet Gynaecol Res, 2004 Oct;30(5):363-7.
    PMID: 15327449
    Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70-year-old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.
  9. Fulltext Tracheal agenesis: a rare cause of unsuccessful tracheal intubation during resuscitation
    Iszuari M, Mazita A, Tan GC, Hayati AR, Shareena I, Cheah FC
    Med J Malaysia, 2010 Dec;65(4):317-8.
    PMID: 21901957
    Tracheal agenesis is a rare congenital airway anomaly that usually results in a fatal outcome. The diagnosis is usually made through post-mortem examination. In the current literature, there has been no reported long-term survival although a few reports claimed prolongation of life of several hours to days. This condition is commonly associated with premature birth, polyhydramnios and a male predominance. In 90% of the cases, it is associated with multiple cardiovascular, gastrointestinal and genitourinary tract anomalies which are incompatible with life. We report a case of a premature newborn with severe respiratory distress, absent cry and cyanosis soon after birth. Attempts at endotracheal intubation failed as it was no possible to negotiate the tube beyond the vocal cords. Needle cricothyrotomy and attempted tracheostomy also failed to secure the airway. The diagnosis was confirmed at post-mortem examination.
  10. The stemness gene expression of cultured human amniotic epithelial cells in serial passages
    Simat SF, Chua KH, Abdul Rahman H, Tan AE, Tan GC
    Med J Malaysia, 2008 Jul;63 Suppl A:53-4.
    PMID: 19024980
    The aim of the study is to evaluate the stemness gene expression of cultured human amniotic epithelial cells (HAECs) in serial passages. HAECs obtained from human term placentae were cultured in F12:DMEM(1:1) + 10% FBS +10ng/ml EGF in serial passages (P0, P1, P2 and P4). Quantitative RT-PCR was used to assess the gene expression analysis. The results showed that cultured HAECs expressed and downregulated the stemness genes expression for Oct-4, Sox-2, Nanog3, FGF4, Rex-1, FZD-9, BST-1 ABCG2. However, vimentin and nestin gene expression were upregulated. The results suggested that cultured HAECs may have pluripotent and multipotent properties.
  11. The spectrum of pathological findings of tonsils in children: A clinicopathological review
    Tan GC, Stalling M, Al-Rawabdeh S, Kahwash BM, Alkhoury RF, Kahwash SB
    Malays J Pathol, 2018 Apr;40(1):11-26.
    PMID: 29704380
    Tonsillectomy is among the most commonly performed operations in children. Although follicular lymphoid hyperplasia is usually the main and only pathologic finding at microscopic examination, a variety of other rare but important pathologic changes may be encountered. This review aims to provide an inclusive practical resource and reference for both training and practising pathologists. It discusses the spectrum of pathologic findings, including both neoplastic and non-neoplastic conditions and provides illustrative images.
  12. Fulltext The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors
    Ko CCH, Chia WK, Selvarajah GT, Cheah YK, Wong YP, Tan GC
    Diagnostics (Basel), 2020 Sep 19;10(9).
    PMID: 32961774 DOI: 10.3390/diagnostics10090721
    Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.
  13. Fulltext The Effect of Probiotics (MCP® BCMC® Strains) on Hepatic Steatosis, Small Intestinal Mucosal Immune Function, and Intestinal Barrier in Patients with Non-Alcoholic Fatty Liver Disease
    Mohamad Nor MH, Ayob N, Mokhtar NM, Raja Ali RA, Tan GC, Wong Z, et al.
    Nutrients, 2021 Sep 14;13(9).
    PMID: 34579068 DOI: 10.3390/nu13093192
    Treatment for non-alcoholic fatty liver disease (NAFLD) currently consists of lifestyle modifications such as a low-fat diet, weight loss, and exercise. The gut microbiota forms part of the gut-liver axis and serves as a potential target for NAFLD treatment. We investigated the effect of probiotics on hepatic steatosis, fibrosis, and biochemical blood tests in patients with NAFLD. At the small intestinal mucosal level, we examined the effect of probiotics on the expression of CD4+ and CD8+ T lymphocytes, as well as the tight junction protein zona occluden-1 (ZO-1). This was a randomized, double-blind, placebo-controlled trial involving ultrasound-diagnosed NAFLD patients (n = 39) who were supplemented with either a probiotics sachet (MCP® BCMC® strains) or a placebo for a total of 6 months. Multi-strain probiotics (MCP® BCMC® strains) containing six different Lactobacillus and Bifidobacterium species at a concentration of 30 billion CFU were used. There were no significant changes at the end of the study in terms of hepatic steatosis (probiotics: -21.70 ± 42.6 dB/m, p = 0.052 vs. placebo: -10.72 ± 46.6 dB/m, p = 0.29) and fibrosis levels (probiotics: -0.25 ± 1.77 kPa, p = 0.55 vs. placebo: -0.62 ± 2.37 kPa, p = 0.23) as measured by transient elastography. Likewise, no significant changes were found for both groups for the following parameters: LiverFAST analysis (steatosis, fibrosis and inflammation scores), alanine aminotransferase, total cholesterol, triglycerides, and fasting glucose. In the immunohistochemistry (IHC) analysis, no significant expression changes were seen for CD4+ T lymphocytes in either group (probiotics: -0.33 ± 1.67, p = 0.35 vs. placebo: 0.35 ± 3.25, p = 0.63). However, significant reductions in the expression of CD8+ T lymphocytes (-7.0 ± 13.73, p = 0.04) and ZO-1 (Z-score = -2.86, p = 0.04) were found in the placebo group, but no significant changes in the probiotics group. In this pilot study, the use of probiotics did not result in any significant clinical improvement in NAFLD patients. However, at the microenvironment level (i.e., the small intestinal mucosa), probiotics seemed to be able to stabilize the mucosal immune function and to protect NAFLD patients against increased intestinal permeability. Therefore, probiotics might have a complementary role in treating NAFLD. Further studies with larger sample sizes, a longer duration, and different probiotic strains are needed to evaluate the real benefit of probiotics in NAFLD.
  14. Fulltext Targeted inactivation of Salmonella Agona metabolic genes by group II introns and in vivo assessment of pathogenicity and anti-tumour activity in mouse model
    Gwee CP, Khoo CH, Yeap SK, Tan GC, Cheah YK
    PeerJ, 2019;7:e5989.
    PMID: 30671294 DOI: 10.7717/peerj.5989
    The fight against cancer has been a never-ending battle. Limitations of conventional therapies include lack of selectivity, poor penetration and highly toxic to the host. Using genetically modified bacteria as a tumour therapy agent has gained the interest of scientist from the past few decades. Low virulence and highly tolerability of Salmonella spp. in animals and humans make it as the most studied pathogen with regards to anti-tumour therapy. The present study aims to construct a genetically modified S. Agona auxotroph as an anti-tumour agent. LeuB and ArgD metabolic genes in ΔSopBΔSopD double knockout S. Agona were successfully knocked out using a Targetron gene knockout system. The knockout was confirmed by colony PCR and the strains were characterized in vitro and in vivo. The knockout of metabolic genes causes significant growth defect in M9 minimal media. Quadruple knockout ΔSopBΔSopDΔLeuBΔArgD (BDLA) exhibited lowest virulence among all of the strains in all parameters including bacterial load, immunity profile and histopathology studies. In vivo anti-tumour study on colorectal tumour bearing-BALB/c mice revealed that all strains of S. Agona were able to suppress the growth of the large solid tumour as compared with negative control and ΔLeuBΔArgD (LA) and BDLA auxotroph showed better efficacy. Interestingly, higher level of tumour growth suppression was noticed in large tumour. However, multiple administration of bacteria dosage did not increase the tumour suppression efficacy. In this study, the virulence of BDLA knockout strain was slightly reduced and tumour growth suppression efficacy was successfully enhanced, which provide a valuable starting point for the development of S. Agona as anti-tumour agent.
  15. Stemness and angiogenic gene expression changes of serial-passage human amnion mesenchymal cells
    Fatimah SS, Tan GC, Chua K, Fariha MM, Tan AE, Hayati AR
    Microvasc Res, 2013 Mar;86:21-9.
    PMID: 23261754 DOI: 10.1016/j.mvr.2012.12.004
    Particular attention has been directed towards human amnion mesenchymal stem cells (HAMCs) due to their accessibility, availability and immunomodulatory properties. Therefore, the aim of the present study was to determine the temporal changes of stemness and angiogenic gene expressions of serial-passage HAMCs.
  16. Fulltext Somatic mutations of CADM1 in aldosterone-producing adenomas and gap junction-dependent regulation of aldosterone production
    Wu X, Azizan EAB, Goodchild E, Garg S, Hagiyama M, Cabrera CP, et al.
    Nat Genet, 2023 Jun;55(6):1009-1021.
    PMID: 37291193 DOI: 10.1038/s41588-023-01403-0
    Aldosterone-producing adenomas (APAs) are the commonest curable cause of hypertension. Most have gain-of-function somatic mutations of ion channels or transporters. Herein we report the discovery, replication and phenotype of mutations in the neuronal cell adhesion gene CADM1. Independent whole exome sequencing of 40 and 81 APAs found intramembranous p.Val380Asp or p.Gly379Asp variants in two patients whose hypertension and periodic primary aldosteronism were cured by adrenalectomy. Replication identified two more APAs with each variant (total, n = 6). The most upregulated gene (10- to 25-fold) in human adrenocortical H295R cells transduced with the mutations (compared to wildtype) was CYP11B2 (aldosterone synthase), and biological rhythms were the most differentially expressed process. CADM1 knockdown or mutation inhibited gap junction (GJ)-permeable dye transfer. GJ blockade by Gap27 increased CYP11B2 similarly to CADM1 mutation. Human adrenal zona glomerulosa (ZG) expression of GJA1 (the main GJ protein) was patchy, and annular GJs (sequelae of GJ communication) were less prominent in CYP11B2-positive micronodules than adjacent ZG. Somatic mutations of CADM1 cause reversible hypertension and reveal a role for GJ communication in suppressing physiological aldosterone production.
  17. Small interfering RNA silencing of interleukin-6 in mesenchymal stromal cells inhibits multiple myeloma cell growth
    Teoh HK, Chong PP, Abdullah M, Sekawi Z, Tan GC, Leong CF, et al.
    Leuk. Res., 2016 Jan;40:44-53.
    PMID: 26626206 DOI: 10.1016/j.leukres.2015.10.004
    Studies demonstrated that mesenchymal stromal cells (MSC) from bone marrow stroma produced high concentration of interleukin-6 (IL-6) that promoted multiple myeloma cell growth. In view of the failure of IL-6 monoclonal antibody therapy to demonstrate substantial clinical responses in early clinical trials, more effective methods are needed in order to disrupt the favourable microenvironment provided by the bone marrow stroma. In this study, we evaluated the short interfering RNA (siRNA)-mediated silencing of IL-6 in MSC and the efficacy of these genetically modified MSC, with IL-6 suppression, on inhibition of U266 multiple myeloma cell growth. IL-6 mRNA and protein were significantly suppressed by 72h post IL-6 siRNA transfection without affecting the biological properties of MSC. Here we show significant inhibition of cell growth and IL-6 production in U266 cells co-cultured with MSC transfected with IL-6 siRNA when compared to U266 cells co-cultured with control MSC. We also show that the tumour volume and mitotic index of tumours in nude mice co-injected with U266 and MSC transfected with IL-6 siRNA were significantly reduced compared to tumours of mice co-injected with control MSC. Our results suggest potential use of RNA interference mediated therapy for multiple myeloma.
  18. Fulltext Small cell variant of anaplastic large cell lymphoma with positive immunoreactivity for CD99
    Shiran MS, Tan GC, Sabariah AR, Chye PC, Pathmanathan R
    Med J Malaysia, 2008 Jun;63(2):150-1.
    PMID: 18942305 MyJurnal
    A 13 year old boy presented with a huge mass on his right arm of 6 months duration. Histopathological examination revealed sheets of malignant small round blue cells with immunopositivity for LCA, CD43, CD45Ro, CD30, EMA, ALK-1 and CD99, and negativity for CD20, TdT, myogenin, myoD1, NSE, bcl-6, bcl-2 and CD10. Fluorescent In-Situ Hybridization (FISH) testing excluded the diagnosis of Ewing's sarcoma/PNET. Pathologists need to be aware of the diagnosis of a small cell variant of ALCL, as well as of the fact that CD99 expression commonly occurs in cases of ALK-positive ALCL, in order to distinguish this entity from Ewing's sarcoma/PNET.
  19. Short hairpin RNA silencing of interleukin-6 in human bone marrow-derived mesenchymal stromal cells inhibits multiple myeloma cell growth
    Teoh HK, Chong PP, Abdullah M, Sekawi Z, Tan GC, Leong CF, et al.
    Pathology, 2016 Feb;48 Suppl 1:S99.
    PMID: 27773219 DOI: 10.1016/j.pathol.2015.12.283
  20. SARS-CoV-2: Reflection beyond the lungs
    Tan GC, Wong YP
    Malays J Pathol, 2022 Dec;44(3):365.
    PMID: 36591706
    No abstract available.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links