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Fulltext Telomerase activation in neoplastic cell immortalization and tumour progression

Looi LM, Ng MH, Cheah PL

Malays J Pathol, 2007 Jun;29(1):33-5.
PMID: 19105326 MyJurnal

The unique ability of tumour cells to proliferate indefinitely is crucial to neoplastic progression as it allows these cells to express the aggressive properties of cancer without the censure of physiological ageing. This is in contrast to normal somatic cells which are subject to a "mitotic clock," a phenomenon that has been linked to telomeric shortening after each round of cell replication, so that eventually the loss of genetic material reaches a critical stage and the cells undergo senescence and cell death. A study was conducted to investigate the role of telomerase, an RNA-containing enzyme that restores the telomere length, in the neoplastic cell immortalization and progression process. Fresh human tissue samples taken from excision specimens received by the Department of Pathology, University of Malaya Medical Centre, were investigated for telomerase activity using a commercial Telomerase PCR-ELISA kit (Boehringer Mannheim). Specimens comprised 33 breast lesions (10 infiltrating breast adenocarcinoma, 13 fibroadenoma and 10 non-neoplastic breast tissue), 27 colonic lesions (17 colonic adenocarcinoma and 10 non-neoplastic colonic mucosa) and 42 cervical lesions (20 cervical carcinoma and 22 non-neoplastic cervical tissues). Telomerase activity was found in 6 (60%) of 10 breast carcinomas, 6 (46%) of 13 fibroadenomas, none of the 10 nonneoplastic breast samples, 3 (17.6%) of 17 colon carcinomas and none of the 10 non-neoplastic colonic mucosal samples, 12 (60%) of 20 cervical carcinoma and 3 (13.6%) of 22 non-neoplastic cervical samples. 5/10 (50%) Stage I, 4/7 (57%) Stage II, 2/2 (100%) Stage III and 1/1 (100%) Stage IV cervical carcinomas showed telomerase activity. These findings support a contributory role for telomerase in tumourigenesis with activation occurring from neoplastic transformation and increasing with tumour progression.
Fulltext Expression of proliferating cell associated protein, Ki-67, supports cellular proliferation in WHO Class IV lupus nephritis

Cheah PL, Kunaseegaran R, Looi LM

Malays J Pathol, 2001 Jun;23(1):27-30.
PMID: 16329544

Ki-67 expression in diffuse proliferative lupus nephritis, WHO Class IV, was compared against normal controls to establish that cellular proliferation is involved in the production of glomerular hypercellularity. Twenty-three histologically confirmed WHO Class IV lupus nephritis and 23 normal control renal tissue were immunohistochemically stained with a polyclonal antibody to Ki-67 (Dako) using the peroxidase labelled streptavidin bioitin kit (Dako). There were 20 females and 3 males, with 17 Chinese and 6 Malays in the WHO Class IV lupus nephritis group. Ages of patients ranged between 10-56 years with a mean of 31.9 years. The normal controls, 20 males and 3 females, and ethnically 9 Indians, 7 Malays, 2 Chinese, and 5 foreign nationals (4 Indonesians and 1 Bangladeshi), had an age range between 15-33 years (mean = 23.3 years). Sixteen (69.6%) WHO Class IV lupus nephritis and 8 (34.8%) normal controls demonstrated Ki-67 immunoreactivity in at least 1 glomerulus (p<0.05). Of the 256 WHO Class IV lupus nephritis non-sclerosed, glomeruli studied, 37 (14.5%) were Ki-67 immunopositive compared with normal controls where 16 (0.7%) of 2159 glomeruli demonstrated Ki-67 (p< 0.01). Cellular proliferative activity, as evidenced by Ki-67 expression, was significantly increased in WHO Class IV lupus nephritis confirming that cell proliferation contributes to glomerular hypercellularity.
Malignant teratoma of the thyroid with predominantly neuroepithelial differentiation. Fine needle aspiration cytologic, histologic and immunocytochemical features of a case

Jayaram G, Cheah PL, Yip CH

Acta Cytol., 2000 May-Jun;44(3):375-9.
PMID: 10833994

BACKGROUND: Teratoma of the thyroid in adults is extremely rare, and most are malignant. Only nine cases have been adequately documented in the English-language literature, and there are no reports detailing the fine needle aspiration (FNA) cytologic characteristics.

CASE: A 32-year-old female presented with a left-sided nodular thyroid mass with left cervical lymphadenopathy. FNA cytology of the thyroid and lymph nodes was done. The cytologic and immunocytochemical features were that of a small round cell tumor with neuroepithelial (NE) differentiation, metastasizing to the cervical nodes. Microscopic study of the thyroidectomy specimen showed a tumor showing an NE pattern with occasional islands of squamous and cuboidal epithelium, leading to a diagnosis of malignant teratoma.

CONCLUSION: Knowledge of FNA cytologic features of rare but highly malignant lesions like thyroid teratomas allow early recognition so that suitable and possibly aggressive treatment protocols can be adopted in the hope of prolonging survival.
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.
Wilms' tumour in Malaysian children: a histopathological study of cases encountered at the University Hospital, Kuala Lumpur over a 22-year period

Cheah PL, Looi LM, Lin HP

Malays J Pathol, 1992 Dec;14(2):111-5.
PMID: 1338998

Formerly thought to have a constant incidence rate throughout the world, Wilms' tumour (nephroblastoma) has been shown to be less common among Asian children. A retrospective demographic and morphological study of Wilms' tumour histologically diagnosed over a 22-year period at the Department of Pathology, University Hospital, Kuala Lumpur was conducted to assess for inherent demographic and morphological differences between tumours in Malaysian children and those of Western populations. Thirty-seven cases of histologically proven Wilms' tumour qualified for inclusion in this study. 19 patients were Chinese, 13 Malay, 4 Indian and 1 Anglo-asian. 21 were male and 16 were female (M:F ratio = 1.3:1). Their ages ranged from 1 month to 4 years. 70.3% of the patients were below 2 years of age. 36 cases had unilateral and 1 bilateral tumours. Of unilateral tumours, 19 involved the left kidney and 17 the right. Histological assessment, based on criteria of the National Wilms' Tumor Study Group, revealed 20 (52.6%) tumours with a mixed pattern while 8 (21.1%) showed epithelial, 7 (18.4%) blastemal and 3 (7.8%) stromal-predominant patterns. Anaplasia was observed in only 2 tumours (5.3%). There was no obvious difference in age range and sex distribution, laterality of tumours and incidence of anaplasia between this and Western studies. No ethnic predilection was observed. A notably larger percentage of cases were below 2 years of age. Also, a larger proportion of epithelial-predominant and a lower proportion of blastemal-predominant tumours was observed compared with patterns reported from Western populations.
Correlation between oestrogen receptor protein expression in infiltrating ductal carcinoma of the breast by immunohistochemistry and cytosol measurements

Looi LM, Yap SF, Cheah PL

Ann Acad Med Singap, 1997 Nov;26(6):750-3.
PMID: 9522973

Fresh frozen neoplastic tissues from 70 infiltrating ductal breast carcinomas were analysed for cytosolic oestrogen receptor (ER) protein content using a solid phase enzyme immunoassay (EIA) method based on a "sandwich" principle (Abbott ER-EIA monoclonal). Formalin-fixed, paraffin-embedded sections from the same carcinomas were examined for nuclear immunoreactivity against a monoclonal antibody for ER protein (Dako) using the standard avidin-biotin complex immunoperoxidase (IP) method after microwave antigen retrieval. The degree of ER positivity by IP was also scored according to a visual estimation of the percentage of cells expressing immunopositivity and the intensity of staining. Twenty-eight (40%) of the carcinomas were ER-positive by EIA and 34 (48.6%) were positive by IP. Twenty-five (35.7%) were ER-positive and 33 (47.1%) were ER-negative by both methods. Nine (12.9%) were ER-negative by EIA but were positive by IP, this discrepancy being ascribed to sampling inadequacy for EIA. However, 3 (4.3%) tumours were ER-positive by EIA and negative by IP. This discrepancy may be variously due to inadequate antigen retrieval, faulty technique and the possibility that the two methods do not measure identical ER proteins. IP appears to have an advantage over EIA in that it has a higher pick-up rate, does not require fresh tissue and can be applied to archival material. However, to reduce false negative estimations, it may be necessary to run IP staining using more than one ER antibody. Standardisation of the IP method for ER is desirable before this method is to be widely adopted in Malaysian laboratories. Quantitation of ER positivity by IP scoring correlated poorly with actual cytosolic levels. Caution should be exercised in attaching patient management value to visual IP scoring.
Correlation between histological grade and c-erbB2 oncoprotein overexpression in infiltrating ductal carcinoma of breast

Looi LM, Cheah PL, Yap SF

Malays J Pathol, 1997 Jun;19(1):35-9.
PMID: 10879240

One hundred and twelve infiltrating ductal carcinoma of breast were studied by the standard avidinbiotin complex immunoperoxidase method on formalin-fixed, paraffin-embedded tissue sections, using a monoclonal antibody to c-erbB-2 oncoprotein. The same tumours were assessed and scored according to the Bloom and Richardson criteria into three histological grades. The distribution of tumours according to grade were: 8 Grade I, 34 Grade II and 70 Grade III. Forty-three (38.4%) tumours showed positive membrane staining for c-erbB-2 oncoprotein. These comprised 7 Grade II and 36 Grade III tumours with c-erbB-2 immunopositivity rates of 20.6% and 51.4% respectively. The oncoprotein was not expressed by Grade I tumours. This study shows a good correlation between c-erbB-2 expression and histological grade, a known prognostic indicator of invasive breast carcinoma. Because the c-erbB-2 oncogene has extensive structural homology to the epidermal growth factor receptor gene, its overexpression can be expected to result in more aggressive tumour behaviour. While it may be regarded as another indicator of poor prognosis breast cancers, its value in the selection of carcinomas less responsive to hormonal therapy and those more suitable for immunotherapy than chemotherapy has been mooted but remains to be clarified.
Immunohistochemical expression of p53 proteins in Wilms' tumour: a possible association with the histological prognostic parameter of anaplasia

Cheah PL, Looi LM, Chan LL

Histopathology, 1996 Jan;28(1):49-54.
PMID: 8838120

Wilms' tumour (nephroblastoma) has been associated with chromosomal abnormalities at the 11p13, 11p15 and 16q regions. A study into the possibility of mutations occurring within p53, the ubiquitous adult tumour suppressor gene, in Wilms' tumour was carried out. Thirty-eight cases were studied. Of these 36 were categorised into the favourable histology group and two into the unfavourable histology group based on the National Wilms' Tumour Study criteria. Archival formalin-fixed, paraffin-embedded tissue sections from each case were stained with a polyclonal (AB565:Chemicon) and a monoclonal (DO7:Dako) antibody raised against p53 protein using a peroxidase-labelled streptavidin biotin kit (Dako). 'Cure' (disease-free survival of 60 months or longer) was documented in 39% of cases with favourable histology tumours. Eleven percent in this group succumbed to the disease. Both cases with unfavourable histology died. Four out of 36 (11%) tumours with favourable histology demonstrated weak to moderate staining with both AB565 and DO7 in more than 75% of tumour cells. In contrast, p53 protein expression in unfavourable histology tumours was significantly increased compared with the favourable histology group (P = 0.021) with both cases demonstrating immunopositivity in > 75% of tumour cells when stained with AB565 and DO7. The intensity of staining ranged from moderate to strong in both cases. It appears from this preliminary study that the immunohistochemical expression of p53 protein in Wilms' tumour, presumably a result of mutation in the p53 tumour suppressor gene, correlates with histological classification, histological categorisation being one of the useful features in the prognostic assessment of Wilms' tumours.
Clear cell sarcoma of kidney: a clinicopathological study of eight cases from Malaysia

Cheah PL, Looi LM, Lin HP

Histopathology, 1992 Oct;21(4):365-9.
PMID: 1328018

Eight cases of clear cell sarcoma of kidney were seen in the Department of Pathology, University Hospital, Kuala Lumpur, Malaysia over the 16-year period from 1973 to 1989. Five of the patients were males. Six patients were Malay, one Chinese and one Indian. The patients' ages ranged from 8 months to 3 years. Clear cell sarcoma was the original diagnosis in two patients while six were diagnosed as blastemal-predominant Wilms' tumours at presentation. Metastases developed in five patients. Metastatic sites included the thoracic vertebra, skull, orbit, humerus, radius, ulna, shoulder, lung and liver. The prolonged survival, of 9 years and 9 months, seen in one patient despite omission of Adriamycin (doxorubicin) from the chemotherapeutic protocol is highlighted. We also emphasise the histological factors which are of help in differentiating clear cell sarcoma from Wilms' tumour.
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.
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
Clear cell sarcoma of kidney: report of the first Malaysian case

Looi LM, Cheah PL, Lin HP

Pathology, 1992 Jan;24(1):34-6.
PMID: 1374551

Clear cell sarcoma of kidney (CCSK) is a rare but distinct tumor of childhood frequently confused with Wilms' tumor (nephroblastoma). It has a characteristic histology, a marked predilection for metastasis to bone, and an aggressive clinical course with a high relapse rate in spite of surgical excision, chemotherapy and radiotherapy. We report the first histologically proven CCSK in a Malaysian patient. This was an 8-mth-old Malay boy who was clinically diagnosed to have stage I Wilms' tumor. Despite treatment, he developed multiple metastases 10 mths after initial presentation and died soon after. Emphasis is placed on recognizing this entity in view of (1) its naturally aggressive behaviour and (2) the prospect of improving prognosis with currently recommended intensified chemotherapeutic regimes. Its immunohistochemical profile of vimentin-positivity and negativity for epithelial membrane antigen, cytokeratin and Factor-8 related antigen is more in favour of a mesenchymal or glomerular origin than a tubular or vascular origin.
Aggressive angiomyxoma of the vulva with an unusual vascular finding

Cheah PL, Looi LM, Sivanesaratnam V

Pathology, 1993 Jul;25(3):250-2.
PMID: 8265242

We report the first documented Malaysian case of aggressive angiomyxoma (AAM) of the vulva. A 56-yr-old woman of Indian ethnic origin presented with a vulval lesion which was clinically mistaken for a Bartholin's cyst. The lesion was surgically excised and a diagnosis of AAM was made histologically. Of particular interest was the finding of foamy and mononuclear inflammatory cells and fibrin in the walls of most of the lesional blood vessels. The patient recovered uneventfully and remains without tumor recurrence at the time of writing 37 mths after initial presentation.
Cost Analysis of Operating an Anatomic Pathology Laboratory in a Middle-Income Country

Cheah PL, Looi LM, Horton S

Am J Clin Pathol, 2017 12 20;149(1):1-7.
PMID: 29267843 DOI: 10.1093/ajcp/aqx088

Objective: To examine the cost of operating an anatomic pathology laboratory in a teaching hospital in Malaysia. Once the cost is determined, compare it with the costs of operating other laboratories in the same hospital, and operating anatomic pathology laboratories in other countries.
Methods: Cost and workload data were obtained from hospital records for 2015. Time allocation of staff between laboratory testing and other activities was determined using assumptions from published workload studies.
Results: The laboratory received 20,093 cases for testing in 2015, and total expenditures were US $1.20 million, ie, $61.97 per case. The anatomic pathology laboratory accounted for 5.2% of the laboratory budget at the hospital, compared to 64.3% for the clinical laboratory and 30.5% for the microbiology laboratory. We provide comparisons to a similar laboratory in the United States.
Conclusions: Anatomic pathology is more costly than other hospital laboratories due to the labor-intensive work, but is essential, particularly for cancer diagnoses and treatment.
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.
Progression of liver disease in non-alcoholic fatty liver disease: a prospective clinicopathological follow-up study

Chan WK, Ida NH, Cheah PL, Goh KL

J Dig Dis, 2014 Oct;15(10):545-52.
PMID: 25060399 DOI: 10.1111/1751-2980.12175

To perform a follow-up study on non-alcoholic fatty liver disease (NAFLD) patients in our previous study using paired liver biopsy.
Fulltext Proliferating cell nuclear antigen (PCNA) activity in hepatocellular carcinoma, benign peri-neoplastic and normal liver

Mun KS, Cheah PL, Baharudin NB, Looi LM

Malays J Pathol, 2006 Dec;28(2):73-7.
PMID: 18376794 MyJurnal

Hepatocellular carcinoma (HCC) is among the ten most common cancers in Malaysian males. As cellular proliferation is an important feature of malignant transformation, we studied the proliferation pattern of normal and benign perineoplastic liver versus hepatocellular carcinoma in an attempt to further understand the tumour transformation process. 39 HCC (21 with accompanying and 18 without cirrhosis) histologically diagnosed at the Department of Pathology, University of Malaya Medical Centre between January 1992 and December 2003 were immunohistochemically studied using a monoclonal antibody to PCNA (Clone PC10: Dako). 20 livers from cases who had succumbed to traumatic injuries served as normal liver controls (NL). PCNA labeling index (PCNA-LI) was determined by counting the number of immunopositive cells in 1000 contiguous HCC, benign cirrhotic perineoplastic liver (BLC), benign perineoplastic non-cirrhotic (BLNC) and NL cells and conversion to a percentage. The PCNA-LI was also expressed as Ojanguren et al's grades. PCNA was expressed in 10% NL, 38.9% BLNC, 76.2% BLC and 71.8% HCC with BLNC, BLC and HCC showing significantly increased (p < 0.05) number of cases which expressed PCNA compared with NL. The number of BLC which expressed PCNA was also significantly increased compared with BLNC. PCNA-LI ranged from 0-2.0% (mean = 0.2%) in NL, 0-2.0% (mean = 0.3%) in BLNC, 0-3.6% (mean = 0.7%) in BLC and 0-53.8% (mean = 7.6%) in HCC with PCNA-LI significantly increased (p < 0.05) only in HCC compared with BLC, BLNC and NL. Accordingly, all NL, BLC and BLNC showed minimal (<5% cells being immunopositive) immunoreactivity on Ojanguren et al's grading system and only HCC demonstrated immunoreactivity which ranged up to grade 3 (75% of cells). From this study, there appears to be a generally increasing trend of proliferative activity from NL to BLNC to BLC and HCC. Nonetheless, BLNC and BLC, like NL, retained low PCNA-LI and only HCC had a significantly increased PCNA-LI compared with the benign categories. This is probably related to the malignant nature of HCC and may reflect the uncontrolled proliferation of the neoplastic hepatocytes.
Evaluation of the monoclonal stool antigen test for Helicobacter pylori in an Asian population with dyspepsia

Bhewa Y, Hilmi I, Cheah PL, Navaratnam P, Goh KL

J Dig Dis, 2007 Nov;8(4):207-10.
PMID: 17970878

Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori.
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.
Immunotactoid glomerulopathy--an unusual deposition disease: report of the first Malaysian case

Cheah PL, Looi LM, Ghazalli R, Chua CT

Malays J Pathol, 1999 Jun;21(1):59-62.
PMID: 10879280

A 31-year-old Malay female presented with nephrotic syndrome without renal impairment. Renal biopsy features were in keeping with immunotactoid glomerulopathy (ITG). Non-Congophilic deposits were seen causing thickening of the glomerular capillary basement membrane with segmental accentuation, and widening of the mesangium. Immunofluorescence examination showed moderate amounts of IgG and C3 in the glomerular capillary walls with some in the mesangium. Ultrastructurally, 20-nm thick fibrils with microtubular organisation were present predominantly in the subendothelial region with similar fibrils in the mesangium. Although immunotactoid glomerulopathy and fibrillary glomerulonephritis (FG) have been recognised as entities with extracellular fibrillary material in the kidney, to date much remains to be clarified regarding these 2 conditions. While the renal biopsy findings in this patient are consistent with ITG, her clinical presentation is unlike that of usual ITG in that she is of a much younger age and has no associated haemopoietic disorder. Response to initial treatment of 8 weeks of prednisolone therapy was poor.

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