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Fulltext Germline mutation analysis of MLH1 and MSH2 in Malaysian Lynch syndrome patients

Zahary MN, Kaur G, Abu Hassan MR, Singh H, Naik VR, Ankathil R

World J Gastroenterol, 2012 Feb 28;18(8):814-20.
PMID: 22371642 DOI: 10.3748/wjg.v18.i8.814

To investigate the protein expression profile of mismatch repair (MMR) genes in suspected cases of Lynch syndrome and to characterize the associated germline mutations.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis/complications; Colorectal Neoplasms, Hereditary Nonpolyposis/genetics*; Colorectal Neoplasms, Hereditary Nonpolyposis/pathology
Germline mutation and protein expression analysis of mismatch repair genes MSH6 and PMS2 in Malaysian Lynch syndrome patients

Zahary MN, Kaur G, Hassan MR, Sidek AS, Singh H, Yeh LY, et al.

Int J Colorectal Dis, 2014 Feb;29(2):261-2.
PMID: 24072394 DOI: 10.1007/s00384-013-1770-1
Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis/genetics*
Fulltext MLH1 and MSH2 gene mutations and polymorphisms in six Malay families with hereditary nonpolyposis colorectal cancer

Wan Khairunnisa Wan Juhari, Khairul Bariah Ahmad Amin Noordin, Wan Faiziah Wan Abdul Rahman, Andee Dzulkarnaen Zakaria, Ahmad Shanwani Mohd Sidek, Muhammad Radzi Abu Hassan, et al.

International Medical Journal Malaysia, 2018;17(1):71-78.
MyJurnal

Background: Hereditary nonpolyposis colorectal cancer (HNPCC) also known as Lynch syndrome is commonly caused by genetic alterations in any of the four mismatch repair (MMR) genes; MLH1, MSH2, MSH6 and PMS2. This is the first study aimed to investigate genetic variants in Malay HNPCC families. Methods: Six Malay HNPCC families who fulfilled any of the Bethesda criteria were recruited into this study. A total of 3 ml of blood was withdrawn from each patient in the families. The samples were further analyzed using polymerase chain reaction and direct sequencing of the selected exons of MLH1 and MSH2 genes. Results: Two missense mutations and four single nucleotide polymorphisms (SNPs) were identified in six patients. These variants in the MLH1 and MSH2 genes were identified in four families who met the revised Bethesda guidelines. In two families, no mutation and polymorphism was identified in both the exon and intron of the respective genes. Of the mutations and polymorphisms identified, five have never been reported in Malay HNPCC families before. A missense mutation was detected in exon 5 of the MLH1 gene, c.394G>C (p.Asp132His) and four mutations and polymorphisms were detected in the MSH2 gene; heterozygous c.211+98T>C and c.211+9C>G and homozygous c.211+98T>C and c.211+9C>G, c.367-86A>C and c.382C>G. Conclusion: The results represented a new spectrum of mutations and polymorphisms in the Malay HNPCC families. However, a larger study involving additional families and analysis is required to determine the impact and nature of the identified mutations and polymorphisms.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis
Contribution of the MLH1 -93G>a promoter polymorphism in modulating susceptibility risk in Malaysian colorectal cancer patients

Nizam ZM, Abdul Aziz AA, Kaur G, Abu Hassan MR, Mohd Sidek AS, Yeh LY, et al.

Asian Pac J Cancer Prev, 2013;14(2):619-24.
PMID: 23621208

BACKGROUND: Colorectal cancer (CRC) exists in a more common sporadic form and less common hereditary forms, associated with the Lynch syndrome, familial adenomatous polyposis (FAP) and other rare syndromes. Sporadic CRC is believed to arise as a result of close interaction between environmental factors, including dietary and lifestyle habits, and genetic predisposition factors. In contrast, hereditary forms such as those related to the Lynch syndrome result from inheritance of germline mutations of mismatch repair (MMR) genes. However, in certain cases, the influence of low penetrance alleles in familial colorectal cancer susceptibility is also undeniable.
AIM: To investigate the genotype frequencies of MLH1 promoter polymorphism -93G>A and to determine whether it could play any role in modulating familial and sporadic CRC susceptibility risk.
METHODS: A case-control study comprising of 104 histopathologically confirmed CRC patients as cases (52 sporadic CRC and 52 Lynch syndrome patients) and 104 normal healthy individuals as controls was undertaken. DNA was extracted from peripheral blood and the polymorphism was genotyped employing PCR-RFLP methods. The genotypes were categorized into homozygous wild type, heterozygous and homozygous variants. The risk association between these polymorphisms and CRC susceptibility risk was calculated using binary logistic regression analysis and deriving odds ratios (ORs).
RESULTS: When risk association was investigated for all CRC patients as a single group, the heterozygous (G/A) genotype showed a significantly higher risk for CRC susceptibility with an OR of 2.273, (95%CI: 1.133-4.558 and p-value=0.021). When analyzed specifically for the 2 types of CRC, the heterozygous (G/A) genotype showed significantly higher risk for sporadic CRC susceptibility with and OR of 3.714, (95%CI: 1.416-9.740 and p-value=0.008). Despite high OR value was observed for Lynch syndrome (OR: 1.600, 95%CI: 0.715-3.581), the risk was not statistically significant (P=0.253).
CONCLUSION: Our results suggest an influence of MLH1 promoter polymorphism -93G>A in modulating susceptibility risk in Malaysian CRC patients, especially those with sporadic disease.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis/genetics*
Analysis of Hereditary Nonpolyposis Colorectal Cancer in Malay Cohorts using Immunohistochemical Screening

Wan Juhari WK, Wan Abdul Rahman WF, Mohd Sidek AS, Abu Hassan MR, Ahmad Amin Noordin KB, Zakaria AD, et al.

Asian Pac J Cancer Prev, 2015;16(9):3767-71.
PMID: 25987035

BACKGROUND: Lynch syndrome (LS) is an inherited predisposition to colorectal, endometrial (uterine) and other cancers. Although most cancers are not inherited, about 5 percent (%) of people who have colorectal or endometrial cancer have the Lynch syndrome. It involves the alteration of mismatch repair (MMR) genes; MLH1, MSH2, MSH6 or PMS2. In this study, we analyzed the expression of MMR proteins in colorectal cancer in a Malay cohort by immunohistochemistry.
MATERIALS AND METHODS: A total of 17 patients were selected fulfilling one of the Bethesda criteria: colorectal cancer diagnosed in a patient aged less than 50 years old, having synchronous and metachronous colorectal cancer or with a strong family history. Immunohistochemical staining was performed on paraffin embedded tumour tissue samples using four antibodies: MLH1, MSH2, MSH6 and PMS2.
RESULTS: Twelve out of 17 patients (70.6%) were noted to have a family history. A total of 41% (n=7) of the patients had abnormal immunohistochemical staining with one or more of the four antibodies. Loss of expression were noted in 13 tumour tissues with a negative staining score <4. Of 13 tumour tissues, four showed loss expression of MLH1. For PMS2, loss of expression were noted in five cases. Both MSH2 and MSH6 showed loss of expression in two tumour tissues respectively.
CONCLUSIONS: Revised Bethesda criteria and immunohistochemical analysis constituted a convenient approach and is recommended to be a first-line screening for Lynch syndrome in Malay cohorts.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis/metabolism*; Colorectal Neoplasms, Hereditary Nonpolyposis/pathology*
Mismatch repair genes expression defects & association with clinicopathological characteristics in colorectal carcinoma

Kaur G, Masoud A, Raihan N, Radzi M, Khamizar W, Kam LS

Indian J Med Res, 2011 Aug;134:186-92.
PMID: 21911971

DNA mismatch repair gene (MMR) abnormalities are seen in 95 per cent of hereditary nonpolyposis colorectal cancer (HNPCC) and 10-15 per cent of sporadic colorectal cancers. There are no data on MMR abnormalities in Malaysian colorectal cancer patients. This study was aimed to determine the frequency of abnormal MMR gene protein expression in colorectal carcinoma in Northern Peninsular Malaysia using immunohistochemistry.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis/genetics; Colorectal Neoplasms, Hereditary Nonpolyposis/pathology
Polymorphisms of cell cycle regulator genes CCND1 G870A and TP53 C215G: Association with colorectal cancer susceptibility risk in a Malaysian population

Zahary MN, Ahmad Aizat AA, Kaur G, Yeong Yeh L, Mazuwin M, Ankathil R

Oncol Lett, 2015 Nov;10(5):3216-3222.
PMID: 26722315

Colorectal cancer (CRC) occurs as a more common sporadic form and a less common familial form. Our earlier analysis of germline mutations of mismatch repair genes confirmed only 32% of familial CRC cases as Lynch syndrome cases. It was hypothesized that the remaining familial aggregation may be 'polygenic' due to single nucleotide polymorphisms (SNPs) of low penetrance genes involved in cancer predisposition pathways, such as cell cycle regulation and apoptosis pathways. The current case-control study involving 104 CRC patients (52 sporadic and 52 familial) and 104 normal healthy controls investigated the contribution of the SNPs cyclin D1 (CCND1) G870A and tumor protein p53 (TP53) C215G in modulating familial and sporadic CRC susceptibility risk. DNA was extracted from peripheral blood and the polymorphisms were genotyped by employing a polymerase chain reaction-restriction fragment length polymorphism method. The association between these polymorphisms and CRC susceptibility risk was calculated using a binary logistic regression analysis and deriving odds ratios (ORs). The A/A variant genotype of CCND1 and G/G variant genotype of TP53 exhibited a significantly greater association with the risk of sporadic CRC [CCND1: OR, 3.471; 95% confidence interval (CI), 1.443-8.350; P=0.005. TP53: OR, 2.829; CI, 1.119-7.152; P=0.026] as well as familial CRC susceptibility (CCND1: OR, 3.086; CI, 1.270-7.497; P=0.019. TP53: OR, 3.048; CI, 1.147-8.097; P=0.030). The results suggest a potential role of the SNPs CCND1 G870A and TP53 C215G in the modulation of sporadic and familial CRC susceptibility risk.

Matched MeSH terms: Colorectal Neoplasms, Hereditary Nonpolyposis