Publications by authors named "Phaik Leng Cheah"

The human epidermal growth factor receptor 2 (HER2) gene is a critical biomarker for determining amplification status and targeting clinical therapies in breast cancer treatment. This study introduces a computer-aided method that automatically measures and scores HER2 gene status from invasive tissue regions of breast cancer using whole slide images (WSI) through silver hybridization (SISH) staining. Image processing and deep learning techniques are employed to isolate untruncated and non-overlapping single nuclei from cancer regions.

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Article Synopsis
  • Fluorescence in situ hybridization (FISH) is the standard method for checking HER2 status in breast cancer, but it has downsides like needing special training and facing signal degradation; an alternative method, silver-enhanced in situ hybridization (SISH), offers a more durable solution for analysis via bright-field microscopy.* -
  • This study introduces a novel deep learning approach to classify Normal, Amplified, and Non-Amplified regions in HER2-SISH whole slide images, aiming to improve accuracy over traditional methods.* -
  • Using a private dataset, the researchers achieved a striking 99.9% patch-level accuracy and an average accuracy of 98% through k-fold cross-validation, suggesting that this deep
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Recent advancements in medical imaging have greatly enhanced the application of computational techniques in digital pathology, particularly for the classification of breast cancer using in situ hybridization (ISH) imaging. HER2 amplification, a key prognostic marker in 20-25% of breast cancers, can be assessed through alterations in gene copy number or protein expression. However, challenges persist due to the heterogeneity of nuclear regions and complexities in cancer biomarker detection.

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Background: Alzheimer's disease (AD) is the most common type of dementia that affects the elderly population. Lately, blood-based proteomics have been intensively sought in the discovery of AD biomarkers studies due to the capability to link external environmental factors with the development of AD. Demographic differences have been shown to affect the expression of the proteins in different populations which play a vital role in the degeneration of cognitive function.

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Alzheimer's Disease (AD) is a neurodegenerative disease that affects cognition and is the most common cause of dementia in the elderly. As the number of elderly individuals increases globally, the incidence and prevalence of AD are expected to increase. At present, AD is diagnosed clinically, according to accepted criteria.

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Background: This study aims to determine the predictors of acquired mutation in advanced non-small cell lung cancer (NSCLC) patients harbouring sensitizing ( mutation following the failure of first- or second-generation -tyrosine kinase inhibitor (TKI).

Methods: This is a retrospective observational study of NSCLC patients with sensitising mutation experiencing disease progression (PD) whilst on first- or second-generation -TKIs with subsequent investigations to detect acquired mutation at the University of Malaya Medical Centre from 1st January 2015 to 31st December 2017.

Results: A total of 87 patients were included.

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Background: The genus Onchocerca Diesing, 1841 includes species of medical importance, such as O. volvulus (Leuckart, 1893), which causes river blindness in the tropics. Recently, zoonotic onchocercosis has been reported in humans worldwide.

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In the recent years, increased understanding of the molecular profiles of non-small cell lung cancer (NSCLC) has allowed for targeted treatment of actionable genetic mutations. The management of NSCLC now requires multiple molecular tests to guide the treatment strategy. In the light of this, there is a need to establish a molecular testing consensus statement for advanced NSCLC patients in Malaysia.

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Background: Except for a few studies with contradictory observations, information is lacking on the possibility of association between DNA mismatch repair (MMR) status and the presence of cancer stem cells in colorectal carcinoma (CRC), two important aspects in colorectal carcinogenesis.

Methods: Eighty (40 right-sided and 40 left-sided) formalin-fixed, paraffin-embedded primary CRC were immunohistochemically studied for CD133, a putative CRC stem cell marker, and MMR proteins MLH1, MSH2, MSH6 and PMS2. CD133 expression was semi-quantitated for proportion of tumor immunopositivity on a scale of 0-5 and staining intensity on a scale of 0-3 with a final score (units) being the product of proportion and intensity of tumor staining.

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Although most of the cervical cancer cases are reported to be closely related to the Human Papillomavirus (HPV) infection, there is a need to study genes that stand up differentially in the final actualization of cervical cancers following HPV infection. In this study, we proposed an integrative machine learning approach to analyse multiple gene expression profiles in cervical cancer in order to identify a set of genetic markers that are associated with and may eventually aid in the diagnosis or prognosis of cervical cancers. The proposed integrative analysis is composed of three steps: namely, (i) gene expression analysis of individual dataset; (ii) meta-analysis of multiple datasets; and (iii) feature selection and machine learning analysis.

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Article Synopsis
  • - Oropharyngeal squamous cell carcinoma (OPSCC) cases in Malaysia are being studied due to their rising incidence linked to HPV, with a focus on p16 as a biomarker for HPV infection, which seems less prevalent in Malaysian patients compared to Western countries.
  • - A study identified 60 OPSCC patients in Malaysia, revealing that 25% had p16 positive tumors, with only 10 of these also testing positive for high-risk HPV DNA, in contrast to a 49% p16 positive rate seen in a UK cohort.
  • - Findings suggest that the incidence of HPV-related OPSCC may be lower in Malaysia, particularly among Indian patients, while potentially increasing among the Chinese ethnicity population; further research is recommended to
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Objective: With an age-standardized incidence rate of 2 per 100 000, esophageal cancer is not common among Malaysians, but they are nevertheless important due to its poor prognosis. The study is to clarify whether the human papillomavirus (HPV) is associated with esophageal cancer in Malaysians as there has been no report to date on this in Malaysians and other South East Asians.

Methods: Altogether 67 esophageal squamous cell carcinomas histologically diagnosed between 1 January 2004 and 31 December 2014 at the Department of Pathology, University of Malaya Medical Center, Malaysia were considered for HPV analysis using two commercially available methods, polymerase chain reaction with flow-through hybridization (21 HPV GenoArray Diagnostic Kit) and multiplex real-time polymerase chain reaction (Anyplex II HPV28 Detection).

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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.

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X-ray repair cross-complementing group 1 (XRCC1) is one of the key components in the base excision repair pathway that repairs erroneous DNA lesions and removes nonbulky base adducts for the maintenance of genome integrity. Studies have revealed that differences in individual DNA repair capacity can impact the interindividual variation in cancer susceptibility, tumour aggressiveness and treatment response. The relationship between XRCC1 and sporadic colorectal cancer (CRC) susceptibility, which is hitherto inconclusive, has been explored in many association studies of different populations.

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Telomeres shorten with physiological aging but undergo substantial restoration during cancer immortalization. Increasingly, cancer studies utilize the archive of formalin-fixed, paraffin-embedded (FFPE) tissues in diagnostic pathology departments. Conceptually, such studies would be confounded by physiological telomere attrition and loss of DNA integrity from prolonged tissue storage.

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Background: In the past, lupus nephritis was histologically classified according to the 1995 WHO Classification. With the introduction of the 2003 ISN/RPS Classification, many nephropathology services converted to this new classification. This study was undertaken to compare both classification systems in a single centre practice.

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Article Synopsis
  • - The study investigates the expression of E-cadherin, a protein crucial for cell adhesion, in 94 colorectal cancer (CRC) samples, focusing on differences between the tumor center and the infiltrating front.
  • - E-cadherin levels were found to be significantly lower at the infiltrating front compared to the tumor center, especially in late-stage (TNM III+IV) and high-grade tumors.
  • - The findings suggest that reduced E-cadherin expression at the infiltrating front may indicate epithelial-mesenchymal transition (EMT), a process linked to tumor progression, and these trends are consistent with observations in CRC from other populations.
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Endometrial cancer is the most common gynecologic cancer in developed countries and is rising in incidence globally. Although the 5-year survival rates are >80%, factors beyond conventional pathologic features that predict clinical outcomes are still being elucidated. The aims of this study were to define the prevalence and associations of deficient mismatch repair (dMMR) protein expression (MLH1, MSH2, MSH6, PMS2) by immunohistochemistry in a multiethnic Southeast Asian cohort with endometrioid endometrial cancer.

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Objective: To perform a follow-up study on non-alcoholic fatty liver disease (NAFLD) patients in our previous study using paired liver biopsy.

Methods: Patients who were included in our previous study on NAFLD and agreed to receive a repeat liver biopsy were included in the study. Their clinical characteristics, laboratory examination results and histological analysis on the repeat liver biopsied specimens were prospectively collected and compared with those in the previous study.

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The tumour suppressor genes, p53 and pRb, are known to play important roles in neoplastic transformation. While molecular routes to the uncontrolled growth of hepatocytes, leading to primary liver cancer have generated considerable interest, the roles of p53 and pRb mutations in hepatocellular carcinoma (HCC) and hepatoblastoma (HB) remain to be clarified. We examined the immunohistochemical expression of p53 and pRb gene products in 26 HCC and 9 HB, sampled into tissue microarray blocks.

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The interesting preponderance of Chinese with colorectal carcinoma (CRC) amongst the three major ethnic groups in Malaysia prompted a study to determine DNA mismatch repair (MMR) status in our CRC and attempt correlation with patient age, gender and ethnicity as well as location, grade, histological type and stage of tumour. Histologically re-confirmed CRC, diagnosed between 1st January 2005 and 31st December 2007 at the Department of Pathology, University of Malaya Medical Centre, were immunohistochemically stained with monoclonal antibodies to MMR proteins, MLH1, MSH2, MSH6 and PMS2 on the Ventana Benchmark XT autostainer. Of the 142 CRC cases entered into the study, there were 82 males and 60 females (M:F=1.

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Between 10 and 25% of individuals with non-alcoholic fatty liver disease (NAFLD) develop hepatic fibrosis leading to cirrhosis and hepatocellular carcinoma (HCC). To investigate the molecular basis of disease progression, we performed a genome-wide analysis of copy number variation (CNV) in a total of 49 patients with NAFLD [10 simple steatosis and 39 non-alcoholic steatohepatitis (NASH)] and 49 matched controls using high-density comparative genomic hybridization (CGH) microarrays. A total of 11 CNVs were found to be unique to individuals with simple steatosis, whilst 22 were common between simple steatosis and NASH, and 224 were unique to NASH.

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Objective: To determine the accuracy of transient elastography (TE) and factors associated with discordance between TE and liver histology in patients with non-alcoholic fatty liver disease (NAFLD).

Methods: The accuracy of TE was assessed and compared with the aspartate aminotransferase-to-platelet ratio index (APRI) in patients with histologically proven NAFLD. Factors associated with discordance between liver histology and TE were analyzed.

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Background: Recent genome-wide association studies demonstrated an association between single nucleotide polymorphisms (SNPs) on the glucokinase regulatory gene (GCKR) with hepatic steatosis. This study attempted to investigate the association of GCKR rs780094 and rs1260326 with susceptibility to non-alcoholic fatty liver disease (NAFLD) and its severity.

Methods: The genotypes were assessed on 144 histologically confirmed NAFLD patients and 198 controls using a Sequenom MassARRAY platform.

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