Displaying publications 81 - 98 of 98 in total

Abstract:
Sort:
  1. Human papillomavirus related diseases in Malaysians
    Cheah PL
    Malays J Pathol, 1994 Jun;16(1):15-7.
    PMID: 16329570
    The surge of information on the aetiological association of the human papillomavirus (HPV) with some epithelial tumours emanating from various centres has prompted the initiation of a large-scale retrospective study at the Department of Pathology, University Hospital Kuala Lumpur to determine the prevalence and importance of this virus in some epithelial tumours of Malaysian patients. A retrospective analysis of 100 cases of large cell non-keratinising carcinoma of the uterine cervix by in-situ hybridisation on archival formalin-fixed, paraffin-embedded tissue has revealed the presence of HPV type 16 in 47% and type 18 in 41% of cases. This gives an overall detection rate of 88% of the two HPV types most commonly encountered in cervical carcinomas. Except for the unusually high frequency of HPV 18 detected in the cases, the overall prevalence is comparable to that reported in studies from most other centres. Although this higher frequency of HPV 18 may be due to geographical variation, the selection of the large cell non-keratinising type of squamous cell cervical carcinoma for study remains a possible reason for this phenomenon. In comparison to cervical carcinomas, HPV appears to be uncommon in penile carcinomas and HPV 6 was detected in only 1 of 23 cases studied.
  2. Alterations in mucin type: an indicator for suspicion of malignant gastric transformation
    Cheah PL, Ramachandran K
    Malays J Pathol, 1994 Jun;16(1):39-42.
    PMID: 16329574
    Mucins are produced by both benign and malignant gastric epithelium. In general, mucins can be classified into neutral and acidic mucins. The latter are of 2 major types, sulphated (sulphomucins) and carboxylated (sialomucins). A retrospective study was initiated at the Department of Pathology, University Hospital, Kuala Lumpur to histochemically study the mucin profiles of cases of intestinal (IGC) and diffuse (DGC) types of gastric carcinoma in Malaysian patients to determine whether a significant change of mucin type occurs in the event of malignant transformation. 42 IGC and 37 DGC were subjected to alcian blue-periodic acid Schiff and high iron diamine-alcian blue histochemical staining. In addition, 18 cases of gastrectomies performed for benign lesions in the stomach served as normal controls. The number of cases of IGC and DGC which exhibited sulphomucin production was significantly increased (p < 0.001) compared to normal controls. Also, the number of cases of DGC which produced neutral mucin were significantly less (p < 0.05) than the control group. However, there was no significant difference between the number of IGC and DGC cases which demonstrated sialomucin production and normal controls. It appears that while not pathognomonic, a lack of neutral mucin production should alert the pathologist to the possibility of a gastric malignancy, in particular DGC. The likelihood of a malignant lesion would be further supported if there is an increased sulphomucin production.
  3. Fulltext Hydatidiform molar pregnancy in Malaysian women: a histopathological study from the University Hospital, Kuala Lumpur
    Cheah PL, Looi LM, Sivanesaratnam V
    Malays J Pathol, 1993 Jun;15(1):59-63.
    PMID: 8277792
    A review of gestational trophoblastic disease diagnosed at the Department of Pathology, University Hospital, Kuala Lumpur from January 1989 to December 1990 using established histological criteria showed 25 complete hydatidiform moles (CHM), 11 partial hydatidiform moles (PHM), 1 invasive mole and 2 choriocarcinoma. The ages of the patients with CHM ranged from 21 to 43 years (mean = 28.5 years) and PHM 20 to 33 years (mean = 27.5 years). The invasive mole occurred in a 42-year-old Malay woman. The two patients with choriocarcinoma were both Chinese and 41 and 46-years old respectively. During the same period, 1,062 non-molar abortions and 13,115 births, inclusive of livebirths and stillbirths were recorded at the University Hospital. The incidence rate of hydatidiform moles was thus estimated to be 1:384 pregnancies. PHM constituted 30% of all molar pregnancies. Hydatidiform moles occurred among the Malays, Chinese and Indians at the rate of 2.43, 2.66 and 3.29 per 1,000 pregnancies respectively. It appears that hydatidiform molar pregnancy has the highest prevalence among the Indians, a finding similar to an earlier Singapore study.
  4. Fulltext In situ hybridisation: principles and applications
    Looi LM, Cheah PL
    Malays J Pathol, 1992 Dec;14(2):69-76.
    PMID: 1304627
    In situ hybridisation (ISH) is based on the complementary pairing of labelled DNA or RNA probes with normal or abnormal nucleic acid sequences in intact chromosomes, cells or tissue sections. Compared with other molecular biology techniques applicable to anatomical pathology, ISH enjoys better rapport with histopathologists because of its similarity to immunohistochemistry. It has the unique advantage over other molecular biology techniques--largely based on probe hybridisation with nucleic acid extracted from homogenised tissue samples--of allowing localisation and visualisation of target nucleic acid sequences within morphologically identifiable cells or cellular structures. Probes for ISH may bear radioactive or non-radioactive labels. Isotopic probes (3H, 32P, 35S, 125I) are generally more sensitive than non-isotopic ones but are less stable, require longer processing times and stringent disposal methods. Numerous non-isotopic labels have been used; of these biotin and digoxigenin are the reporters of choice. Optimised non-isotopic systems of equivalent sensitivity to those which use radioactive-labelled probes have been described. In ISH, finding the optimal balance between good morphological preservation of cells and strong hybridisation signals is crucial. Tissue fixation and retention of cytoskeletal structures, unfortunately, impede diffusion of probes into tissues. ISH sensitivity is also influenced by inherent properties of the probe and hybridisation conditions. Although ISH is largely a research tool, it is already making strong inroads into diagnostic histopathology. It has been applied for the detection of various infective agents particularly CMV, HPV, HIV, JC virus, B19 parvovirus, HSV-1, EBV, HBV, hepatitis delta virus, Chlamydia trachomatis, salmonella and mycoplasma in tissue sections.(ABSTRACT TRUNCATED AT 250 WORDS)
  5. Squamous cell carcinoma related antigen in uterine cervical carcinoma
    Cheah PL, Yap SF, Looi LM, Sivanesaratnam V
    Malays J Pathol, 1991 Jun;13(1):37-41.
    PMID: 1795560
    Squamous cell carcinoma-related antigen (SCC-Ag), first described by Kato and Torigoe in 1977, has been cited by various workers as a serological marker for some epithelial neoplasms. The most well-studied is its association with carcinoma of the uterine cervix. In January 1989, we embarked on a prospective, multivariate study at the University Hospital, Kuala Lumpur to assess the usefulness of serologically assaying SCC-Ag (using the Abbott RIA diagnostic kit) in our patients with carcinoma of the uterine cervix. We were also interested to ascertain whether SCC-Ag is a 'general' marker for all histological types of cervical carcinoma or specific for squamous carcinoma. From the time of commencement to June 1990, 35 newly-diagnosed and histologically-proven cases were entered into the study. Of these, 4 were keratinising squamous carcinoma, 18 large cell non-keratinising carcinoma, 3 adenosquamous carcinoma, 7 adenocarcinoma and 3 carcinoma-in-situ. Our preliminary results show that all keratinising squamous carcinoma and 1/3 each of large cell non-keratinising carcinoma, adenosquamous carcinoma and carcinoma-in-situ had positive pre-therapy serum SCC-Ag levels (i.e greater than 2 ng/ml, 2 ng/ml being an arbitrarily selected 'cut-off' value). In contrast, no adenocarcinoma was serologically positive. In addition, keratinising squamous carcinoma had the highest mean pre-therapy serum SCC-Ag level. The results imply that serum SCC-Ag is related to the (1) presence of squamous and not glandular differentiation and (2) degree of squamous differentiation.
  6. The pathology of tumour and "tumour-like" lesions of bone in the University Hospital, Kuala Lumpur
    Peh SC, Cheah PL, Sengupta S
    Malays J Pathol, 1988 Aug;10:45-50.
    PMID: 3252076
  7. Screening for microsatellite instability in colorectal carcinoma: Practical utility of immunohistochemistry and PCR with fragment analysis in a diagnostic histopathology setting
    Cheah PL, Li J, Looi LM, Koh CC, Lau TP, Chang SW, et al.
    Malays J Pathol, 2019 Aug;41(2):91-100.
    PMID: 31427545
    Since 2014, the National Comprehensive Cancer Network (NCCN) has recommended that colorectal carcinoma (CRC) be universally tested for high microsatellite instability (MSI-H) which is present in 15% of such cancers. Fidelity of resultant microsatellites during DNA replication is contingent upon an intact mismatch repair (MMR) system and lack of fidelity can result in tumourigenesis. Prior to commencing routine screening for MSI-H, we assessed two commonly used methods, immunohistochemical (IHC) determination of loss of MMR gene products viz MLH1, MSH2, MSH6 and PMS2 against PCR amplification and subsequent fragment analysis of microsatellite markers, BAT25, BAT26, D2S123, D5S346 and D17S250 (Bethesda markers) in 73 unselected primary CRC. 15.1% (11/73) were categorized as MSI-H while deficient MMR (dMMR) was detected in 16.4% (12/73). Of the dMMR, 66.7% (8/12) were classified MSI-H, while 33.3% (4/12) were microsatellite stable/low microsatellite instability (MSS/MSI-L). Of the proficient MMR (pMMR), 95.1% (58/61) were MSS/MSI-L and 4.9% (3/61) were MSI-H. The κ value of 0.639 (standard error =0.125; p = 0.000) indicated substantial agreement between detection of loss of DNA mismatch repair using immunohistochemistry and the detection of downstream microsatellite instability using PCR. After consideration of advantages and shortcomings of both methods, it is our opinion that the choice of preferred technique for MSI analysis would depend on the type of laboratory carrying out the testing.
  8. FISHing for 1p19q codel in oligodendroglioma
    Kong PL, Cheah PL, Mun KS, Chiew SF, Lau TP, Koh CC, et al.
    Malays J Pathol, 2020 Dec;42(3):369-376.
    PMID: 33361717
    Together with isocitrate dehydrogenase (IDH) mutation, co-deletion of 1p19q (1p19q codel) is a prerequisite for diagnosis of oligodendroglioma, making it imperative that histopathology laboratories introduce testing for 1p19q codel. To date there is still no consensus reference range and cut-offs that confirm deletion of 1p or 19q. We embarked on determining our reference range in 11 formalinfixed, paraffin-embedded non-neoplastic brain tissue using fluorescence in situ hybridisation (FISH) with the Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular Inc., USA). At same time we attempted to validate our methodology in 13 histologically-confirmed IDH-mutant oligodendrogliomas. For 1p, percentage cells with deletion (range=8-23%; mean±SD = 15.73±5.50%) and target: control (1p36:1q25) ratio (range = 0.89-0.96; mean±SD = 0.92±0.03) in non-neoplastic brain, differed significantly (p<0.000) from oligodendroglioma (percentage cells with deletion: range = 49-100%; mean±SD = 82.46±15.21%; target:control ratio range:0.50-0.76; mean±SD = 0.59±0.08). For 19q, percentage cells with deletion (range = 7-20%; mean±SD = 12.00±3.49%) and target:control (19q13/19p13) ratio (range:0.90-0.97; mean±SD = 0.94±0.02) in non-neoplastic brain also differed significantly from oligodendroglioma (percentage cells with deletion: range = 45-100%; mean±SD = 82.62±18.13%; target:control ratio range:0.50-0.78; mean±SD = 0.59±0.09). Using recommended calculation method, for diagnosis of 1p deletion, percentage of cells showing deletion should be >32-33% and/or target:control ratio <0.83. For 19q, percentage of cells showing deletion should be >22% and target:control ratio <0.88. Using these cut-offs all 13 oligodendroglioma demonstrated 1p19q codel.
  9. Fulltext Research on cancer diagnosis in Malaysia: current status
    Looi LM, Zubaidah Z, Cheah PL, Cheong SK, Gudum HR, Iekhsan O, et al.
    Malays J Pathol, 2004 Jun;26(1):13-27.
    PMID: 16190103
    Cancer is a major morbidity and mortality concern in Malaysia. Based on National Cancer Registry data, the Malaysian population is estimated to bear a cancer burden of about 40,000 new cases per year, and a cumulative lifetime risk of about 1:4. Cancer research in Malaysia has to consider needs relevant to our population, and resources constraints. Hence, funding bodies prioritise cancers of high prevalence, unique to our community and posing specific clinical problems. Cancer diagnosis is crucial to cancer management. While cancer diagnosis research largely aims at improvements in diagnostic information towards more appropriate therapy, it also impacts upon policy development and other areas of cancer management. The scope of cancer diagnosis upon which this paper is based, and their possible impact on other R&D areas, has been broadly categorized into: (1) identification of aetiological agents and their linkages to the development of precancer and cancer (impact on policy development, cancer prevention and treatment), (2) cancer biology and pathogenesis (impact on cancer prevention, treatment strategies and product development), (3) improvements in accuracy, sensitivity and specificity in cancer detection, monitoring and classification (impact on technology development) and (4) prognostic and predictive parameters (impact on treatment strategies). This paper is based on data collected by the Working Group on Cancer Diagnosis Research for the First National Conference on Cancer Research Coordination in April 2004. Data was collated from the databases of Institutions/Universities where the authors are employed, the Ministry of Science, Technology and Innovation (MOSTI) and targeted survey feedback from key cancer researchers. Under the 7th Malaysia Plan, 76 cancer projects were funded through the Intensified Research in Priority Areas (IRPA) scheme of MOSTI, amounting to almost RM15 million of grant money. 47(61.8%) of these projects were substantially in cancer diagnosis, accounting for 65.6% (RM 9.7 million) of cancer project funds. The 8th Malaysia Plan saw a change in research strategy. The IRPA agency fielded several top-down projects which encouraged a multicentre and multidisciplinary approach. This resulted in larger funding per project i.e. RM32 million for 49 projects. There was also a surge of interest in drug development and natural products. Because of this shift in direction, cancer diagnosis projects constituted only 51% of IRPA-funded cancer projects. Nonetheless funding for cancer diagnosis research has exceeded that of the 7th Malaysia Plan, being RM12.5 million by March 2004. The majority of such research is carried out at the Universities, engaging a large number of young scientists and postgraduate students (51 MSc and 21 PhD). A lot of research findings presented at scientific meetings have not yet been published and there is a glaring shortage of patents and commercialization of research findings (such as creation of test kits). Because diagnosis is very much a part of clinical practice, many researchers felt satisfied and confident that their work will be translated into practice and will significantly improve diagnostic services in Malaysia. National guidelines and consensus development on at least three malignancies i.e. breast cancer, oral cancer and lymphoma, have substantial basis in local R&D work. Problems encountered in research included (1) insufficient funding to realize research objectives, (2) lack of local expertise (most research assistants are inexperienced BSc graduates with no or minimal research experience), (3) inadequate technical support from vendors during equipment failure, (4) inexperienced Institutional development units to assist in product development, (5) lack of venture capital for commercialization of findings, and (6) inadequate incentives to undertake research. Researchers pointed out that plans to promote research should include the establishment of (1) regional and national cancer tissue banks, (2) a National Cancer Research Institute, (3) a dedicated cancer research fund, (4) a registry of cancer researchers, (5) national research coordinators, (6) improved coverage by the National Cancer Registry, (7) more international collaboration, (8) a better career structure for researchers, (9) improved Institutional support for product realization, and (10) better recognition for cancer researchers.
  10. Immunohistochemistry usage profile in a Malaysian tertiary hospital's histopathology laboratory
    Cheah PL, Chau YT, Looi LM
    Malays J Pathol, 2021 Dec;43(3):353-359.
    PMID: 34958056
    INTRODUCTION: Immunohistochemistry (IHC) was commenced in 1986 at the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur and its usage has grown for the past 30 over years, hence it was felt that a review was timely in view of the scarcity of literature on IHC usage.

    MATERIALS AND METHODS: All cases received by the Department of Pathology for histopathological examination between 1 July 2018 and 30 June 2019 were retrieved from the Laboratory Information System (LIS). All the IHC requests over this period were tabulated, with the exception of renal, muscle, rectal and nerve biopsies with their pre-defined algorithms for stains and cytological specimens. IHC stains performed solely for purpose of directing targeted treatment were also not included.

    RESULTS: Immunohistochemistry was performed in 2044 (21.1%) of the total of 9686 cases, with a total of 5969 IHC stains performed i.e. 2.9 (5969/2044) IHC stains per case. All 91 antibodies available were used at least once during the study. 14 histopathologists (5 with < 10-years and 9 with ≥ 10-years postgraduate specialist experience) reported on the cases with no significant difference (p=0.90) in their usage of IHC stains. Among the most common IHC stains used, requests for Ki67 and MNF116 showed higher standard deviations compared with p63, CK7 and S100 among the histopathologists. From the relatively higher standard deviation for Ki67 and MNF116 it appeared that there was a greater difference in the requesting pattern between histopathologists for these two antibodies.

    CONCLUSION: The rate of use of IHC in our centre seems compatible with that of an academic centre. Personal preferences of the histopathologists, rather than years of postgraduate specialist experience appeared to influence the rate of usage and choice of antibodies.

  11. ERRATUM: Phyllodes tumours of the breast: retrospective analysis of a University Hospital's experience
    Toh YF, Cheah PL, Looi LM, Teoh KH, Tan PH
    Malays J Pathol, 2016 08;38(2):175.
    PMID: 27568677
    No abstract available.
  12. Cyclooxygenase-2 (COX2) expression in adenocarcinoma surpasses that of squamous cell carcinoma in the uterine cervix
    Marutha Muthu AK, Cheah PL, Koh CC, Chew MF, Toh YF, Looi LM
    Malays J Pathol, 2017 Dec;39(3):251-255.
    PMID: 29279587 MyJurnal
    Over the years, adenocarcinoma (ADC), which has a worse prognosis than squamous cell carcinoma (SCC) of the cervix, has shown an increasing trend. Cyclooxygenase-2 (COX2) expression which has been associated with worse prognosis in several solid cancers was studied for its association with SCC and ADC of the cervix. 35 histologically re-confirmed SCC and 35 ADC were immunohistochemically stained for COX2 using a mouse monoclonal antibody to COX2 (1:100; Dako: Clone CX-294) on a Ventana Benchmark XT. The histoscore was computed as intensity of staining, semi-quantitated on a scale of 0-3 with 0 = negative, 1 = weak, 2 = moderate and 3 = strong staining intensity; multiplied by percentage of immunopositivity on a scale of 0-4 with 0 = <1%, 1 = 1-25%, 2 = 26-50%, 3 = 51-75% and 4 = ≥75% of immunopositive tumour cells. Histoscore 1-3/12 was considered as low and ≥4/12 as high COX2 expression. SCC affected Chinese more than Malays, while Malays had more ADC (p = 0.032). Mean age at presentation of SCC (57.5 years) was about a decade later than ADC at 47.9 years (p = 0.002). 30/35 (85.7%) of SCC and 34/35 (97.1%) of ADC expressed COX2. Histoscores of ADC (median = 4.0, IQR = 3.0-6.0) was significantly higher (p = 0.014) than those of SCC (median = 3.0, IQR = 2.0-3.0). High histoscores (≥4/12) were more frequent in ADC (55.9%) compared with SCC (26.7%) (p = 0.018), implicating COX2, either directly or indirectly, as a possible player in influencing the poorer outcome of ADC compared with SCC.
  13. Gastrointestinal stromal tumour in a jejunal diverticulum: The eighth reported case worldwide with a brief review of the literature
    Chiew SF, Toh YF, Looi LM, Cheah PL
    Malays J Pathol, 2023 Dec;45(3):473-478.
    PMID: 38155388
    Jejunal diverticulosis is uncommon and so are gastrointestinal stromal tumours (GIST) arising in the jejunum. GIST arising in a jejunal diverticulum is a rarity and to date there are only 7 cases in the English literature. Our case of GIST occurring in a jejunal diverticulum of a 48-year-old lady would be the first reported in Malaysia and the 8th in the world. As in most cases, the clinical presentation and radiological findings of this patient were non-specific. With a history of acute abdominal pain, vomiting and fever, the patient was provisionally diagnosed as a case of twisted ovarian cyst and subjected to laparotomy. An intact roundish jejunal diverticulum 5.0 cm x 5.0 cm, about 50 cm distal to the duodeno-jejunal junction was found and resected with a segment of small intestine. Microscopic examination showed a tumour of the cut open diverticular wall, with epithelioid to spindled cells, demonstrating a mitotic rate of 1-2 per 5 mm2, confined to, while infiltrating the wall of the diverticulum. The immunohistochemical profile of positive staining for CD117, DOG-1, smooth muscle actin and CD34, and negative expression of desmin and S100 protein, clinched the diagnosis of GIST. Based on the AFIP Criteria for risk stratification,1 the patient was categorised as having moderate risk for disease progression, and was not offered further targeted imatinib as an immediate measure. The patient has remained well at the time of writing i.e. 8 months following excision, and continues on active surveillance by the surgical and oncological teams, with the option of imatinib, should the necessity arise. This case is presented not merely for the sake of documenting its rarity, but as a reminder to stay alert for uncommon conditions in histopathology practice.
  14. Epithelial-mesenchymal transition profiles in triple negative breast carcinoma may explain its aggressive nature
    Chiew SF, Looi LM, Cheah PL, Teoh KH, Chang SW, Abdul Sani SF
    Malays J Pathol, 2023 Dec;45(3):363-374.
    PMID: 38155378
    Epithelial-mesenchymal transition (EMT) is increasingly explored in cancer progression. Considering that triple negative (TN) breast cancer has the poorest survival among molecular subtypes, we investigated 49 TN, 45 luminal and 25 HER2-enriched female breast carcinomas for EMT expression (using E-cadherin and vimentin immunohistochemistry) against lymphovascular and/or lymph node invasion. E-cadherin and vimentin expressions were semi-quantitated for positive- cancer cells (0=0-<1%, 1=1-10%, 2 =11-50%, 3=>50%) and staining intensity (0=negative, 1=weak, 2=moderate, 3=strong), with final score (low=0-4 and high=6-9) derived by multiplying percentage and intensity scores for each marker. Low E-cadherin and/or high vimentin scores defined EMT positivity. Low E-cadherin co-existing with high vimentin defined "complete" (EMT-CV), while low E-cadherin (EMT-C) or high vimentin (EMT-V) occurring independently defined "partial" subsets. 38 (31.9%) cancers expressed EMT, while 59.2 % TN, 13.3% luminal and 12% HER2-enriched cancers expressed EMT (p<0.05). Among the cancers with lymphovascular and/or lymph node invasion, EMT positivity by molecular types were 66.7% TN, 7.4% luminal and 11.8% HER2-enriched (p<0.05). Although EMT-V, associated with stem-cell properties was the dominant TN EMT profile, EMT-CV, a profile linked to vascular metastases, was encountered only in TN. EMT appears important in TN cancer and different EMT profiles may be associated with its aggressive nature.
  15. Fulltext Actinomyces infection of the mastoid: a rare entity
    Subha ST, Raman R, Cheah PL, Soo Hoo TS
    Med J Malaysia, 2004 Dec;59(5):680-1.
    PMID: 15889574
    A rare case of mastoid infection caused by actinomyces israelii is presented. This patient underwent exploratory mastoidectomy followed by long term oral pencillin. She responded well to the treatment and has been asymptomatic on follow up to date.
  16. Human papillomavirus in cervical cancers of Malaysians
    Cheah PL, Looi LM, Sivanesaratnam V
    J Obstet Gynaecol Res, 2011 Jun;37(6):489-95.
    PMID: 21349124 DOI: 10.1111/j.1447-0756.2010.01386.x
    With cervical carcinoma remaining the second leading cancer among Malaysian women, it is imperative to clarify the prevalence of human papillomavirus (HPV) in this respect, considering the dearth of local information.
  17. Recent trends in histological pattern of cervical carcinoma among three ethnic groups in Malaysia
    Cheah PL, Looi LM, Sivanesaratnam V
    J Obstet Gynaecol Res, 1999 Dec;25(6):401-6.
    PMID: 10680337
    To study the trend of different histological types of cervical carcinoma among the 3 major ethnic groups in Malaysia.
  18. FK506 rescue therapy for acute renal allograft rejection
    Goh BL, Morad Z, Cheah PL, Chua CT, Tan SY
    Transplant Proc, 1998 Nov;30(7):3592-3.
    PMID: 9838574
Related Terms
Filters
Contact Us

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

External Links