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Fulltext An immunohistochemical and molecular study of gastrointestinal stromal tumours

Teong YT, Teo ST, Tan LP, Wu BQ, Peh SC

Med J Malaysia, 2006 Dec;61(5):526-33.
PMID: 17623951 MyJurnal

Gastrointestinal stromal tumour (GIST) is a rare but most common mesenchymal tumour in the gastrointestinal tract. Although GIST research has been carried out extensively worldwide, it has yet to be studied in Malaysia. To establish the immunohistochemical expression pattern of CD117 (c-KIT), CD34, S-100 and Desmin, the incidence of c-KIT and PDGFRA genes mutation in GISTs, and correlate it with clinicopathological parameters. Eleven clinically diagnosed GISTs were stained for CD117, CD34, Desmin and S-100 protein by immunohistochemical technique, and c-KITand PDGFRA gene mutations were studied by PCR-CSGE-DNA sequencing method. All GISTs (7 cases) stain positive for CD117, and co-expressed CD34. None of these cases express Desmin, and only one expressed S-100 protein focally. Fifty-seven percent (4/7 cases) of GIST harboured mutations at exon 11 of c-KIT gene, and they were all high risk and malignant cases. No mutation was detected at exons 9, 13 and 17 of KIT gene, and exons 12 and 18 of PDGFRA gene. Immunohistochemistry using a panel of antibodies shows consistent pattern of CD117 and CD34 expression in GIST, and mutational study may be a useful prognostic marker for kinase inhibitor treatment of GIST.

Matched MeSH terms: Immunohistochemistry
Fulltext Significance of Bcl-2 and Bax proteins in cervical carcinogenesis: an immunohistochemical study in squamous cell carcinoma and squamous intraepithelial lesions

Cheah PL, Looi LM

Malays J Pathol, 2006 Jun;28(1):1-5.
PMID: 17694953 MyJurnal

Sixteen low grade (LSIL), 22 high grade (HSIL) squamous intraepithelial lesions, 28 invasive (13 stage I and 15 stage II-IV) squamous cell carcinoma (SCC) and 15 benign cervices were immunohistochemically studied for involvement of Bcl-2 and Bax proteins in cervical carcinogenesis. 4-microm sections of the cases were immunostained for Bcl-2 (Clone 124: Dako) and Bax (Dako) and staining intensity was rated as 1 (light), 2 (moderate) and 3 (strong) and percentage cellular staining as 0 (negative), 1 (1-25%), 2 (26-50%), 3 (51-75%) and 4 (>75%) with score derived by multiplying staining intensity and percentage positivity. The cut-off value, indicating upregulated expression, was computed as >2 for Bcl-2 and >8 for Bax. Bcl-2 was upregulated (p < 0.05) in HSIL and Bax in SCC when compared with benign cervical squamous epithelium. Bcl-2 expression was confined to the lower third of the epithelium in the benign cervices and LSIL. In HSIL, expression reached the middle and upper thirds. 4 (30.8%) HSIL with upregulated Bcl-2 demonstrated intensification of staining around the basement membrane. SCCs showed "diffuse" (evenly distributed) or "basal" (intensified staining around the periphery of the invading tumour nests) expression of Bcl-2. Of the 5 SCCs with upregulated Bcl-2, 1 of 2 (50%) stage I and 3 (100%) stage II-IV tumours exhibited the "basal" pattern. Benign cervical squamous epithelium, LSIL, HSIL and SCC showed a generally diffuse Bax expression. Thus, Bcl-2 and Bax appeared to be upregulated at different stages of cervical carcinogenesis, Bcl-2 in HSIL and Bax after invasion. Intensification of staining of Bcl-2 at the basement membrane in some HSIL and SCC is interesting and may augur for increased aggressiveness.

Matched MeSH terms: Immunohistochemistry
RET and p53 expression in thyroid follicular adenoma: a study of 52 cases with 14 years follow-up

Othman NH, Omar E, Mahmood MH, Madhavan M

Malays J Pathol, 2005 Dec;27(2):91-8.
PMID: 17191391

Most previous studies on RET and p53 proteins have focused on thyroid papillary carcinoma. We investigated the role of RET and p53 protein expressions using immunohistochemistry on 52 cases of thyroid follicular adenomas and studied the follow-up records of these patients. The range of follow-up period was 3 to 14 years. The patients were between 15 and 71 years of age with a median age of 34.5 years. There were 46 females and 6 males. Except for 3 cases, all patients were Malays. The minimum volume of the tumour was 1000 mm3 and the maximum was 512,000 mm3 with a median of 270,000 mm3. Eleven (21.2%) cases showed RET expression. RET expression was not statistically significant when cross-tabulated against sex (p = 0.322), ethnicity (p = 0.518), age (p = 0.466) and symptom duration (p = 0.144). Six (11.5%) of 52 cases showed p53 immunopositivity. p53 expressions were also not significantly correlated to the clinical parameters above. There was no correlation between RET and p53 protein expressions. The only statistically significant finding was the association of tumour volume with duration of symptoms (p = 0.05). All patients are alive at the time of writing. 3 had recurrent goitre, 2 of these were diagnosed as colloid goitre while the third was a follicular lesion. One patient suffered from depression requiring anti-depressant treatment. In conclusion, unlike papillary carcinoma in which the roles of ret and p53 oncogenes are known, their roles in influencing the behaviour of follicular adenoma has not been ascertained.

Matched MeSH terms: Immunohistochemistry
Human telomerase reverse transcriptase expression in oral carcinogenesis--a preliminary report

Kumar SK, Zain RB, Ismail SM, Cheong SC

J Exp Clin Cancer Res, 2005 Dec;24(4):639-46.
PMID: 16471328

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, is strongly associated with telomerase activity implicated in cellular immortalization and tumorigenesis. In situ detection of hTERT will aid in determining the localization of telomerase positive cells. The aim of this study was to detect hTERT protein expression in multistep oral carcinogenesis using paraffin embedded tissue samples, and to study the relationship of hTERT expression with different histological stages in oral carcinogenesis. Normal (n = 4), hyperplastic (n = 4), dysplastic (n = 4) and neoplastic (n = 10) oral epithelia representing different histological stages in oral carcinogenesis were included in the study. hTERT protein detection was done by immunohistochemistry (IHC) technique. Nuclear staining intensities were noted and the hTERT-labelling index was determined. Dysplastic and neoplastic oral epithelia showed an increased percentage of hTERT positive cells (Grade 4: > 50% positive staining nuclei) with intense staining in the basal, parabasal and superficial layers of the epithelia, unlike normal oral mucosa which showed intense staining only in the basal and parabasal cell layers, which are the normal proliferative progenitor compartments. hTERT protein expression was elevated with the corresponding advancement of the histological stages of oral carcinogenesis, from normal to hyperplasia to dysplasia to carcinoma. There seems to be an upregulation of hTERT protein expression during the progression of oral cancer, therefore, this may indicate the feasibility of IHC detection of hTERT protein in oral carcinogenesis as a potential diagnostic or prognostic marker.

Matched MeSH terms: Immunohistochemistry
Fulltext Malignant melanoma of the gastrointestinal tract presenting as a bleeding gastric ulcer

Noraidah M, Jasmi AY

Malays J Pathol, 2003 Jun;25(1):57-61.
PMID: 16196379

Malignant melanoma involving the gastrointestinal tract is diagnosed antemortem in only a small percentage of patients with the disease. Presenting symptoms are often non-specific, causing a diagnostic problem. The vast majority of such melanomas are metastatic from a cutaneous primary, however there is evidence that the tumour can arise de novo in the gastrointestinal system. We report a 74-year-old man with malignant melanoma with an unusual presentation simulating a symptomatic gastric ulcer. He presented with epigastric pain, haematemesis and melaena. Explorative laparotomy revealed a large ulcerated tumour with several pigmented satellite nodules in the proximal stomach, multiple ileal nodules and widespread nodal and liver metastases. Proximal gastrectomy and limited small bowel resection was performed. Histology revealed the tumour to be composed of nests of epithelioid cells with melanin pigment. The tumour cells showed immunohistochemical positivity for S100 protein and HMB45 antibodies. This report emphasizes that melanoma should be a diagnostic consideration in patients with gastric ulcer.

Matched MeSH terms: Immunohistochemistry
Malignant cervical teratoma in an adult presenting with impending airway obstruction

Lukman MR, Jasmi AY, Sarinah B, Nurismah MI, Aishah MA

Asian J Surg, 2005 Jul;28(3):227-9.
PMID: 16024322

Extragonadal teratomas and germ cell tumours are uncommon. Most teratomas of the head and neck present in the paediatric age group. Occurrence of such tumours in an adult is extremely rare and, to date, less than 40 cases have been reported in the literature. We report a case of a young man presenting with impending airway obstruction secondary to a malignant teratoma of the neck.

Matched MeSH terms: Immunohistochemistry
Fulltext Diagnostic flex-rigid pleuroscopic biopsy of parietal pleura for exudative pleural effusions in suspected malignant and tuberculosis cases: a retrospective study of 219 cases

Lad L, Samsudin AT, Kannan K, Makki JS, Mohamed M

Malays J Pathol, 2015 Aug;37(2):101-7.
PMID: 26277666 MyJurnal

This study was carried out to ascertain the aetiology of exudative pleural effusions when other diagnostic investigations such as pleural fluid and sputum examination for cytology and acid fast bacilli fail to yield a definitive diagnosis and to differentiate between tuberculosis and malignancy in cases suspicious of malignancy.

Matched MeSH terms: Immunohistochemistry
Fulltext Obstructive jaundice in small cell lung carcinoma

Mokhtar Pour A, Masir N, Isa MR

Malays J Pathol, 2015 Aug;37(2):149-52.
PMID: 26277673 MyJurnal

Small cell lung carcinoma (SCLC) commonly metastasizes to distant organs. However, metastasis to the pancreas is not a common event. Moreover, obstructive jaundice as a first clinical presentation of SCLC is extremely unusual. This case reports a 51-year-old male with SCLC, manifesting with obstructive jaundice as the initial clinical presentation. Endoscopic retrograde cholangiopancreatograghy (ERCP) and abdominal computed tomography (CT) scan showed a mass at the head of the pancreas. The patient underwent pancreatoduodenectomy (Whipple procedure). Histopathology revealed a chromogranin- A-positive poorly-differentiated neuroendocrine carcinoma of the pancreas. No imaging study of the lung was performed before surgery. A few months later, a follow-up CT revealed unilateral lung nodules with ipsilateral hilar nodes. A lung biopsy was done and histopathology reported a TTF- 1-positive, chromogranin A-positive, small cell carcinoma of the lung. On review, the pancreatic tumour was also TTF-1-positive. He was then treated with combination chemotherapy (cisplatin, etoposide). These findings highlight that presentation of a mass at the head of pancreas could be a manifestation of a metastatic tumour from elsewhere such as the lung, and thorough investigations should be performed before metastases can be ruled out.

Matched MeSH terms: Immunohistochemistry
An immunohistochemical study of the lining epithelium of odontogenic keratocyst

Siar CH, Ng KH

J Nihon Univ Sch Dent, 1995 Sep;37(3):163-9.
PMID: 7490610

The lining epithelium of 15 cases of odontogenic keratocyst (OKC) was evaluated immunohistochemically. The peroxidase-antiperoxidase technique was applied to study the distribution of polyclonal keratin and S-100 protein while the indirect method was used to examine monoclonal vimentin and desmin reactivity. Consistent positive keratin staining was revealed in the lining epithelium of all 15 OKCs with additional intense staining in the stratum corneum. None of the cases showed vimentin or desmin reactivity within the lining epithelium elements. One of the 15 cysts studied showed positive S-100 protein staining in the nuclei of the lining epithelial cells. The pertinent literature on the immunophenotyping of the lining epithelium of OKC is reviewed.

Matched MeSH terms: Immunohistochemistry
An immunohistochemical study of two cases of either peripheral odontogenic fibroma (WHO type) or peripheral ameloblastoma

Chong Huat Siar, Kok Han Ng

J Nihon Univ Sch Dent, 1996 Mar;38(1):52-6.
PMID: 8648412

Two cases of either peripheral odontogenic fibroma (POF) (WHO type) or peripheral ameloblastoma are reported. Their immunohistochemical characteristics were investigated in an attempt to clarify their histogenesis. The results showed that the epithelial component of this neoplasm tended to retain its distinct odontogenic character and expressed a keratin profile different from that of the overlying oral epithelium from which both cases most probably originated. The connective tissue element of these tumors was vimentin-positive and S-100 protein negative, confirming their mesodermal nature but precluding the possibility of ectomesenchymal derivation. No reactivity for desmin was noted.

Matched MeSH terms: Immunohistochemistry
Unusual granular cell odontogenic tumor. Report of two undescribed cases with features of granular cell ameloblastoma and plexiform granular cell odontogenic tumor

Siar CH, Ng KH

J Nihon Univ Sch Dent, 1993 Jun;35(2):134-8.
PMID: 7692017

Granular cell ameloblastoma (GCA) is a well recognized variant of follicular ameloblastoma with extensive granular cell change. In contrast, plexiform granular cell odontogenic tumor (PGCOT) is a rare and recently described lesion characterized histologically by a monophasic plexiform pattern of granular cells. In this paper, two cases of an unusual granular cell odontogenic tumor exhibiting combined features of these two entities are described along with their immunohistochemical characteristics. The granular cells of both the GCA and PGCOT areas showed similar patterns of expression for keratin and S-100, which differed from those of typical ameloblastoma. No reactivity for desmin or vimentin was noted. The histomorphologic and immunohistochemical features of these hybrid tumors suggest that the granular cells present have a common origin, most probably the odontogenic epithelium.

Matched MeSH terms: Immunohistochemistry
Patterns of expression of intermediate filaments and S-100 protein in desmoplastic ameloblastoma

Siar CH, Ng KH

J Nihon Univ Sch Dent, 1993 Jun;35(2):104-8.
PMID: 7692015

Seventeen cases of desmoplastic ameloblastoma were examined immunohistochemically. Immunoperoxidase techniques were applied for detection of keratin, desmin, vimentin and S-100 protein expression in these tumors. The tumor epithelium of desmoplastic ameloblastoma exhibited weak, focal, inconstant keratin staining, weak, variable expression of S-100 protein, desmin immunoreactivity of mild to moderate intensity and vimentin non-reactivity. The pertinent literature on the immunohistochemistry of ameloblastomas is briefly reviewed.

Matched MeSH terms: Immunohistochemistry
Quantitative comparison of apoptosis to cell proliferation and p53 protein in breast carcinomas

Zheng WQ, Zhan RZ

Anal. Quant. Cytol. Histol., 1998 Feb;20(1):1-6.
PMID: 9513685

To clarify the correlation between apoptosis and tumor cell proliferative activity in human breast cancer and to investigate their relevance to p53 protein.

Matched MeSH terms: Immunohistochemistry
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.

Matched MeSH terms: Immunohistochemistry
Further biological, serological and biochemical characterization of North American, European and Southeast Asian strains of bovine herpesvirus 1 compared with other alphaherpesvirinae members

Trépanier P, Minocha HC, Ibrahim AL, Sheikh-Omar AR, Montpetit C, Lecomte J, et al.

Vet Microbiol, 1988 Dec;18(3-4):219-31.
PMID: 2852870

Hemagglutination activity, structural protein profiles and neutralization assays were used in a comparative study of bovine herpesvirus 1 strains from the U.S.A., Canada, Great Britain, Denmark and Malaysia with equine, feline and human herpesviruses in order to further characterize the bovine herpesvirus 1 hemagglutinin. Bovine herpesvirus 1 strains of different geographical origins all showed hemagglutinating activity for mouse erythrocytes; furthermore, feline herpesvirus 1 was also shown to hemagglutinate mouse erythrocytes. Analyses of partly purified viruses showed that a distinctive and specific polypeptides profile is associated with each species of herpesviruses used in our study; strains of bovine herpesvirus 1 from North America, Europe and Southeast Asia however, presented a remarkable similarity as to their electrophoretic protein patterns. A protein similar to the 97-kDa bovine viral hemagglutinin was not identified with the hemagglutinating feline herpesvirus. An important neutralization epitope on the bovine viral hemagglutinin was also not found on feline, equine and human herpesviruses but was identified on all bovine strains tested from North America, Europe and Southeast Asia stressing the importance of the bovine hemagglutinin for eventual prophylactic purposes.

Matched MeSH terms: Immunohistochemistry
The pattern of amyloidosis in a Malaysian patient population

Looi LM

Histopathology, 1991 Feb;18(2):133-41.
PMID: 1901294

Congo red screening of 27,052 routine biopsy specimens from 22,827 patients over a 5 1/2-year period in the Department of Pathology, University of Malaya detected 186 cases of amyloidosis. The categories of amyloidosis encountered and their prevalences in relation to each other were: systemic AL (5.9%); systemic AA (3.2%); isolated atrial (14%); primary localized cutaneous (7.5%); other primary localized deposits (3.2%); localized intratumour (58%); and dystrophic (8.6%). A third of patients with systemic AL amyloidosis had coexistent immunocyte abnormality. The commonest underlying pathology for systemic AA amyloidosis was leprosy. Notable among the types of localized amyloidosis revealed by this study were isolated atrial amyloidosis, which appeared to complicate chronic rheumatic heart disease, and intratumour amyloidosis complicating nasopharyngeal carcinoma. Other tumours in which amyloid deposits were observed included basal cell carcinoma, islet cell tumour and medullary carcinoma of the thyroid. Dystrophic amyloidosis was observed in fibrotic tissues, such as damaged cardiac valves and osteoarthritic joints. Heredofamilial amyloidosis, senile systemic amyloidosis and degenerative cerebral amyloidosis were notably absent from this study.

Matched MeSH terms: Immunohistochemistry
Pattern of Epstein-Barr virus association in childhood non-Hodgkin's lymphoma: experience of university of malaya medical center

Peh SC, Nadarajah VS, Tai YC, Kim LH, Abdullah WA

Pathol. Int., 2004 Mar;54(3):151-7.
PMID: 14989737

The pattern of childhood non-Hodgkin's lymphoma (NHL) usually differs in adults. The most common subtypes are lymphoblastic, Burkitt's and anaplastic large cell lymphoma. Recent data indicate that a higher risk of developing lymphoma is associated in children of certain ethnic origins. The difference is probably related to the underlying etiological factors of these diseases, and Epstein-Barr virus (EBV) is a strong candidate. The present study aims to determine the disease pattern of childhood lymphomas in the University Hospital Kuala Lumpur, for a direct comparison to the reported data of adults from the same medical center. A total of 69 and 34 childhood NHL and Hodgkin's lymphomas, respectively, were retrieved. The most common subtypes were lymphoblastic (23 cases), Burkitt's (25 cases) and anaplastic large cell lymphomas (9 cases). Epstein-Barr virus association was more prevalent in B-cell (23%) than T-cell (12%) lymphomas. The most common EBV-associated tumor was Burkitt's lymphoma, and there was an increased risk of EBV association for Burkitt's lymphoma in Chinese patients. In conclusion, the pattern of childhood lymphoma in Malaysia is relatively similar to children elsewhere in the world. The EBV association of B- and T-NHL differs between children and adults from the same medical center because of differences in the subtype composition in these two age groups.

Matched MeSH terms: Immunohistochemistry
Fulltext Expression of NAD(P)H quinone dehydrogenase 1 (NQO1) is increased in the endometrium of women with endometrial cancer and women with polycystic ovary syndrome

Atiomo W, Shafiee MN, Chapman C, Metzler VM, Abouzeid J, Latif A, et al.

Clin Endocrinol (Oxf), 2017 Nov;87(5):557-565.
PMID: 28748640 DOI: 10.1111/cen.13436

OBJECTIVE: Women with a prior history of polycystic ovary syndrome (PCOS) have an increased risk of endometrial cancer (EC).
AIM: To investigate whether the endometrium of women with PCOS possesses gene expression changes similar to those found in EC.
DESIGN AND METHODS: Patients with EC, PCOS and control women unaffected by either PCOS or EC were recruited into a cross-sectional study at the Nottingham University Hospital, UK. For RNA sequencing, representative individual endometrial biopsies were obtained from women with EC, PCOS and a woman unaffected by PCOS or EC. Expression of a subset of differentially expressed genes identified by RNA sequencing, including NAD(P)H quinone dehydrogenase 1 (NQO1), was validated by quantitative reverse transcriptase PCR validation (n = 76) and in the cancer genome atlas UCEC (uterine corpus endometrioid carcinoma) RNA sequencing data set (n = 381). The expression of NQO1 was validated by immunohistochemistry in EC samples from a separate cohort (n = 91) comprised of consecutive patients who underwent hysterectomy at St Mary's Hospital, Manchester, between 2011 and 2013. A further 6 postmenopausal women with histologically normal endometrium who underwent hysterectomy for genital prolapse were also included. Informed consent and local ethics approval were obtained for the study.
RESULTS: We show for the first that NQO1 expression is significantly increased in the endometrium of women with PCOS and EC. Immunohistochemistry confirms significantly increased NQO1 protein expression in EC relative to nonmalignant endometrial tissue (P

Matched MeSH terms: Immunohistochemistry
Infectious bursal disease virus tissue tropism and pathogenesis of the infection in chickens by application of in situ PCR, immunoperoxase and HE staining

Hussein EA, Hair-Bejo M, Liew PS, Adamu L, Omar AR, Arshad SS, et al.

Microb Pathog, 2019 Apr;129:195-205.
PMID: 30738178 DOI: 10.1016/j.micpath.2019.01.049

Infectious bursal disease is one of an OIE list of notifiable diseases. Chicken is the only host that manifests clinical signs and its pathogenicity is correlated with the distribution of antigens in organs. This study was conducted to determine disease pathogenesis and virus tissue tropism by in situ PCR, immunoperoxidase staining (IPS), and HE staining. Twenty four chickens were infected with very virulent Infectious Bursal Disease Virus (vvIBDV). Fifteen chickens were kept as a control group. Infected chickens were sacrificed at hrs 2, 4, 6, 12, days 1, 2, 4, and 6 post-inoculation (pi). While, control chickens were euthanized on days 0, 1, 2, 4, and 6 pi. Different tissues were collected, fixed in 10% buffered formalin, and processed. At hr 2 pi, virus was detected in intestinal, junction of the proventriculus and gizzard, cecal tonsil, liver, kidney, and bursa of Fabricius. At hr 4 pi, virus reached spleen, and at hr 6 pi, it entered thymus. At hr 12 pi, virus concentration increased in positive tissues. The latest invaded tissue was muscle on day 1 pi. Secondary viraemia occurred during 12-24 h pi. In situ PCR was the most sensitive technique to highlight obscure points of infection in this study.

Matched MeSH terms: Immunohistochemistry
No difference in the occurrence of mismatch repair defects and APC and CTNNB1 genes mutation in a multi-racial colorectal carcinoma patient cohort

Tan LP, Ng BK, Balraj P, Lim PK, Peh SC

Pathology, 2007 Apr;39(2):228-34.
PMID: 17454753

BACKGROUND AND AIMS: Colorectal cancers of different subtypes involve different pathogenic pathways like the Wnt and the mutator pathways. In this study, we screened 73 colorectal cancer cases from a multi-racial group for genetic and expression profile defects with the aim of correlating these with patients' clinicopathological characteristics.
METHODS: Mutation screening of the entire coding region of APC and exon 3 of CTNNB1, loss of heterozygosity (LOH) of APC, and microsatellite instability (MSI) status were assessed for 44 patients with available paired frozen normal and tumour tissues. In addition, 29 cases with available paraffin embedded tumour blocks were screened for mutation in exon 3 of CTNNB1, the APC mutation cluster region (codon 1286-1513), and hMLH1, hMSH2, hMSH6 protein expressions by immunohistochemistry method.
RESULTS: In our study, 15/73 cases showed APC mutations (20.5%), 1/73 cases had CTNNB1 mutation (1.4%), 5/32 cases had APC LOH (15.6%), and 16/70 (22.9%) cases revealed at least some form of mismatch repair (MMR) defect. Tumour grade (poor differentiation) was found to correlate significantly with right-sided tumour and mucinous histology (p = 0.01879 and 0.00320, respectively). Patients of younger age (below 45 years) more often had tumours of mucinous histology (p = 0.00014), while patients of older age (above 75 years) more often had tumours on the right side of the colon (p = 0.02448). Tumours of the mucinous histology subtype often had MMR defects (p = 0.02686). There was no difference in the occurrence of APC and CTNNB1 mutations and MMR defects found within our multi-racial colorectal cancer patient cohort.
CONCLUSION: Our findings support the notion that racial factor may not be related to the occurrence of MMR defects and APC and CTNNB1 mutations in our multi-racial patient cohort.

Matched MeSH terms: Immunohistochemistry

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