MyMedR

Oral candidal species among smokers and non-smokers

Rasool S, Siar CH, Ng KP

J Coll Physicians Surg Pak, 2005 Nov;15(11):679-82.

PMID: 16300700

To determine the various oral Candidal species among healthy Malaysian adults.

Sarcoid-like foreign body reaction in body piercing: a report of two cases

Ng KH, Siar CH, Ganesapillai T

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1997 Jul;84(1):28-31.

PMID: 9247945

We report two cases of body piercing as a religious practice that subsequently led to the development of granulomatous nodules at previously punctured sites of the skin and oral mucosa. These lesions were diagnosed as sarcoid-like foreign body reaction after other possible causes including sarcoidosis, tuberculosis, tuberculoid leprosy, fungal infections, viral infections, and Crohn's disease were excluded.

Denture hyperplasia and oncocytic metaplasia

Siar CH, Ng KH, Ngui CH

Ann Dent, 1992;51(1):27-8.

PMID: 1632623

A case of denture hyperplasia of the upper labial sulcus with concomitant oncocytic metaplastic changes is described. The patient concerned is an elderly male wearing an ill-fitting upper full denture.

Leiomyoma of the incisive papilla region: a case report

Ng KH, Siar CH, Abdul Latif H

Ann Dent, 1992;51(1):29-31.

PMID: 1632624

Leiomyomas are benign neoplasms of smooth muscle origin. They represent rare entities in the oral cavity. A case arising from the incisive papilla region of a 3-month-old infant is described and the histogenesis as well as the biologic potential of this tumor are discussed.

Calcifying fibroblastic granuloma. A case report

Taiyeb Ali TB, Siar CH

J N Z Soc Periodontol, 1997.

PMID: 9522721

Adenomatoid odontogenic tumour: a case study with radiographic differential diagnostic considerations

Siar CH, Ong ST, Ng KH

Singapore Dent J, 1996 Jul;21(1):19-22.

PMID: 10597178

Adenomatoid odontogenic tumours (AOT) are benign, hamartomatous odontogenic lesions that not uncommonly mimic a dentigerous cyst radiographically. Such a case as found involving an unerupted left maxillary canine in a 19-year-old Chinese female is described. The differential diagnosis of some common odontogenic cysts and neoplasms occurring in Malaysians, that may present in a dentigerous relationship to an unerupted tooth is discussed. A brief review of the radiographic literature on AOT is also included.

Kimura's disease: a case report

Ng KH, Siar CH, Loh HT

Ann Dent, 1991;50(2):26-7.

PMID: 1785910

The clinical and histologic features of Kimura's disease are briefly outlined. A case presenting as a subcutaneous nodule in the region of the angle of the right mandible of a 20-year-old male is presented. The relationship of this disease to angiolymphoid hyperplasia with eosinophilia is discussed.

A study on the prevalence of oral habits in 100 cases of squamous cell carcinoma in Malaysia

Ng KH, Siar CH, Ramanathan K, Murugasu P

Ann Dent, 1986;45(2):7-10.

PMID: 3468879

Calcifying odontogenic cysts in peninsular Malaysia. A report of 30 cases

Ng KH, Siar CH, Murugasu P

Ann Dent, 1986;45(2):19-22.

PMID: 3468872

Odontogenic keratocyst: a study of 53 cases in Malaysia

Siar CH, Ng KH, Murugasu P

Ann Dent, 1986;45(2):15-8.

PMID: 3468871

Plexiform granular cell odontogenic tumor: unicystic variant

Siar CH, Ng KH, Jalil NA

Oral Surg. Oral Med. Oral Pathol., 1991 Jul;72(1):82-5.

PMID: 1891247

Plexiform granular cell odontogenic tumor of the mandible has recently been described. The cardinal histopathologic feature, as its name suggests, is a monophasic plexiform pattern of granular cells; the principal tumor in the differential diagnosis is granular cell ameloblastoma. Unlike the two previously reported cases of plexiform granular cell odontogenic tumor, which occurred as solid tumors in elderly men, the lesion reported here is a unicystic variant occurring in a middle-aged woman.

Fulltext Clinical statistics of the adenomatoid odontogenic tumour in Malaysia (1968-1986)

Siar CH, Ng KH, Murugasu P

Med J Malaysia, 1987 Dec;42(4):284-9.

PMID: 3331408

The records of the Division of Stomatology were reviewed for the incidence of adenomatoid odontogenic tumour diagnosed between 1968 and 1986. Forty-five cases were found. The prevalence of this tumour according to their age, sex, site and its distribution in the various states in Malaysia are reported. Many features were similar to previous reports of this entity. However the incidence of AOT appears to be higher among the Indians and lower in the Chinese population. It is suggested that this feature may be peculiar to Malaysians.

Fulltext Congenital fibrous epulis: a case report

Majid ZA, Siar CH, Ling KC

Med J Malaysia, 1986 Jun;41(2):179-82.

PMID: 3821617

An unusual case of fibrous epulis in a newborn is presented. The clinical appearance, histological features and method of treatment are described. A short review of the literature is also included.

Combined granular cell ameloblastoma and plexiform granular cell odontogenic tumour

Siar CH, Ng KH, Chia TY

Singapore Dent J, 1990 Dec;15(1):35-7.

PMID: 2097728

Granular cell ameloblastomas are uncommon lesions accounting for about 3-5% of all histologic subtypes of ameloblastoma. The plexiform granular cell odontogenic tumour, on the other hand, is a newly described lesion characterised by a monophasic plexiform pattern of granular cells. This article reports a tumour found occurring in the left mandible of a 67-year-old Indian male which histologically showed features of both the aforementioned lesions.

Parenchyma-stromal interleukin-1 alpha and interleukin-6 overexpressions in ameloblastoma correlate with the aggressive phenotype

Goh YC, Chan SW, Siar CH

Malays J Pathol, 2019 Dec;41(3):303-311.

PMID: 31901915

INTRODUCTION: Ameloblastoma is a benign but locally invasive odontogenic epithelial neoplasm with a high recurrence rate after treatment. The two main subsets encountered clinically are unicystic (UA) and solid/multicystic ameloblastoma (SMA). Currently neoplastic progression of many tumour types are believed to be related to parenchyma-stromal cell-cell interactions mediated by cytokines notably interleukins (IL). However their roles in ameloblastoma remain ill-understood.

MATERIALS AND METHODS: Thirty-nine formalin-fixed paraffin-embedded ameloblastoma cases comprising unicystic ameloblastoma (n=19) and solid/multicystic ameloblastoma (n=20) were subjected to IHC staining for IL-1α, IL-1β, IL-6 and IL-8. A semi-quantitative method was used to evaluate the expression levels of these cytokines according to cell types in the tumoural parenchyma and stroma.

RESULTS: Major findings were upregulations of IL-1α and IL-6 in SMA compared to UA. Both cytokines were heterogeneously detected in the tumoural parenchyma and stroma. Within the neoplastic epithelial compartment, IL-1α expression was more frequently detected in PA-like cells in UA whereas it was more frequently encountered in SR-like cells in SMA. IL-6 demonstrated higher expression levels in the stromal compartment of SMA. IL-1β and IL-8 were markedly underexpressed in both tumour subsets.

CONCLUSIONS: Overexpression of IL-1α in SMA suggests that this growth factor might play a role in promoting bone resorption and local invasiveness in this subtype. The expression levels of IL-1α and IL-6 in three cellular localizations indicate that parenchymal-stromal components of ameloblastoma interact reciprocally via IL-1α and IL-6 to create a microenvironment conducive for tumour progression.

Fulltext Adenomatoid odontogenic tumour: gross and histogical examination of 45 cases

Siar CH, Ng KH, Murugasu P

Singapore Med J, 1987 Apr;28(2):180-9.

PMID: 3629275

This paper represents a reappraisal of the gross and histological features of 45 cases of adenomatoid odontogenic tumours as observed under conventional light and fluorescence microscopy. The findings conformed largely to those of previous studies. Usage of the term adenomatoid odontogenic tumour in preference to its old name 'adenoameloblastoma' is emphasized. The differential diagnosis of this entity from the ameloblastoma and salivary gland tumours is discussed.

Fulltext Differential expression of stem cell-like proteins in normal, hyperplastic and dysplastic oral epithelium

Barakat SM, Siar CH

J Appl Oral Sci, 2015 Jan-Feb;23(1):79-86.

PMID: 25760270 DOI: 10.1590/1678-775720140245

The identification of stem cells (SC) remains challenging. In the human oral mucosal epithelium, these cells are believed to be in the basal layer (stem cell niche), but their exact location is unclear. The aim of this study was to examine the dysplastic oral epithelium for these SC-like proteins in order to assess their diagnostic value as biomarkers complementing the histological grading of dysplasia.

Differential expression of transcription factors Snail, Slug, SIP1, and Twist in ameloblastoma

Siar CH, Ng KH

J Oral Pathol Med, 2014 Jan;43(1):45-52.

PMID: 23560539 DOI: 10.1111/jop.12065

Epithelial-to-mesenchymal transition (EMT) via the mechanism of transcription repression is a crucial process for the induction of invasiveness in many human tumors. Ameloblastoma is a benign odontogenic epithelial neoplasm with a locally infiltrative behavior. Twist, an EMT promoter, has been implicated in its invasiveness. The roles of the other transcription factors remain unclarified.

Claudin expression and tight junction protein localization in the lining epithelium of the keratocystic odontogenic tumors, dentigerous cysts, and radicular cysts

Siar CH, Abbas SA

Oral Surg Oral Med Oral Pathol Oral Radiol, 2013 May;115(5):652-9.

PMID: 23601220 DOI: 10.1016/j.oooo.2013.02.013

The aim of this study was to evaluate the expression and localization of tight junction proteins (TJPs) or claudins in the keratocystic odontogenic tumor (KCOT) and to correlate with its biological behavior.

Cellular protrusions--lamellipodia, filopodia, invadopodia and podosomes--and their roles in progression of orofacial tumours: current understanding

Alblazi KM, Siar CH

Asian Pac J Cancer Prev, 2015;16(6):2187-91.

PMID: 25824735

BACKGROUND: Protrusive structures formed by migrating and invading cells are termed lamellipodia, filopodia, invadopodia and podosomes. Lamellipodia and filopodia appear on the leading edges of migrating cells and function to command the direction of the migrating cells. Invadopodia and podosomes are special F-actin-rich matrix-degrading structures that arise on the ventral surface of the cell membrane. Invadopodia are found in a variety of carcinomatous cells including squamous cell carcinoma of head and neck region whereas podosomes are found in normal highly motile cells of mesenchymal and myelomonocytic lineage. Invadopodia-associated protein markers consisted of 129 proteins belonging to different functional classes including WASP, NWASP, cortactin, Src kinase, Arp 2/3 complex, MT1-MMP and F-actin. To date, our current understanding on the role(s) of these regulators of actin dynamics in tumors of the orofacial region indicates that upregulation of these proteins promotes invasion and metastasis in oral squamous cell carcinoma, is associated with poor/worst prognostic outcome in laryngeal cancers, contributes to the persistent growth and metastasis characteristics of salivary gland adenoid cystic carcinoma, is a significant predictor of increased cancer risk in oral mucosal premalignant lesions and enhances local invasiveness in jawbone ameloblastomas.

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