Microsatellite instability and its correlation with clinicopathological features in a series of thyroid tumors prevalent in iodine deficient areas

Vaish, Minal; Mishra, Anjali; Kaushal, Manish; Mishra, Saroj Kanta; Mittal, Balraj

doi:10.1038/emm.2004.18

Cited by 12 publications

(8 citation statements)

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“…Although it has been suggested that in thyroid tumours, MSI is an important indicator of defects in the MMR system [28], the data presented in this study showed no relationship between MLH1 expression and MSI status. In addition, a previous study on colorectal cancer showed that methylation of another DNA repair gene, MGMT , is also linked to MSI [22,29].…”

Section: Discussioncontrasting

confidence: 87%

Correlation of MLH1 and MGMTexpression and promoter methylation with genomic instability in patients with thyroid carcinoma

et al. 2013

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BackgroundGene silencing of the repair genes MLH1 and MGMT was shown to be a mechanism underlying the development of microsatellite instability (MSI), a phenotype frequently associated with various human malignancies. Recently, aberrant methylation of MLH1, MGMT and MSI were shown to be associated with mutations in genes such as BRAF, RAS and IDH1 in colon and brain tumours. Little is known about the methylation status of MLH1 and MGMT in thyroid tumours and its association with MSI and mutational status.MethodsIn a series of 96 thyroid tumours whose mutational profiles of BRAF, IDH1 and NRAS mutations and RET/PTC were previously determined, we investigated MLH1 and MGMT expression and methylation status by qPCR and methylation-specific PCR after bisulphite treatment, respectively. MSI was determined by PCR using seven standard microsatellite markers.ResultsSamples with point mutations (BRAF, IDH1 and NRAS) show a decrease in MLH1 expression when compared to negative samples. Additionally, malignant lesions show a higher MSI pattern than benign lesions. The MSI phenotype was also associated with down-regulation of MLH1.ConclusionsThe results of this study allow us to conclude that low expression of MLH1 is associated with BRAF V600E mutations, RET/PTC rearrangements and transitions (IDH1 and NRAS) in patients with thyroid carcinoma. In addition, a significant relationship between MSI status and histological subtypes was found.

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Section: Discussioncontrasting

confidence: 87%

Correlation of MLH1 and MGMTexpression and promoter methylation with genomic instability in patients with thyroid carcinoma

et al. 2013

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“…However, in most studies a diVerent panel of microsatellite markers for thyroid cancer is used comprising BAT26, BAT-40, TGFbetaRII, hMSH3, and other. Using these markers, MSI and LOH is detected in up to 66% in thyroid tumors (Vaish et al 2003(Vaish et al , 2004Onda et al 2001). Apparently, our microsatellite marker set is inapplicable for MSI and LOH detection in thyroid tumors.…”

Section: Discussionmentioning

confidence: 94%

Large proportion of low frequency microsatellite-instability and loss of heterozygosity in pheochromocytoma and endocrine tumors detected with an extended marker panel

Kupka

Haack

Zdichavsky

et al. 2007

J Cancer Res Clin Oncol

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“…Moreover, most of the studies, focused on thyroid carcinoma, have documented that genetic alterations, such as microsatellite instability (MSI) and loss of heterozygosity (LOH), constitute an integral part of thyroid carcinogenesis (25)(26)(27). Although, opposite to FTC (follicular thyroid carcinoma), LOH in PTC is a rather rare mechanism of loss of gene function (26,28).…”

Section: Introductionmentioning

confidence: 99%

Aberrant methylation as a main mechanism of TSGs silencing in PTC

Czarnecka

Pastuszak-Lewandoska²,

Migdalska-Sęk³

et al. 2011

Front Biosci

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In the present study the role of tumour suppressor genes (TSGs) hypermethylation and genetic instability of LOH/MSI type in thyroid tumorigenesis was assessed. Expression, methylation status and presence of LOH/MSI were analyzed for 8 TSGs selected from imprinted (IR) and non-imprinted (NIR) chromosomal regions in papillary thyroid carcinomas (PTCs) and nodular goitres (NGs). The results show that methylation-induced gene silencing occurs at an early step of thyroid carcinogenesis and involves multiple genes. Genetic changes of LOH/MSI type are less frequent. In PTC samples, the lack of significant differences in the frequency of LOH in IR and NIR suggests that it is not a key mechanism changing the pattern of gene expression. Co-methylation observed both in NG and PTC raises a possibility that, in thyroid tissue, methylation-induced silencing may occur not only in malignant transformation but also in functional context. We did not recognize any of the studied TSGs - in regard to aberrant methylation status or LOH/MSI frequency - as a selective molecular marker in thyroid tumorigenesis.

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Microsatellite instability and its correlation with clinicopathological features in a series of thyroid tumors prevalent in iodine deficient areas

Cited by 12 publications

References 11 publications

Correlation of MLH1 and MGMTexpression and promoter methylation with genomic instability in patients with thyroid carcinoma

Correlation of MLH1 and MGMTexpression and promoter methylation with genomic instability in patients with thyroid carcinoma

Large proportion of low frequency microsatellite-instability and loss of heterozygosity in pheochromocytoma and endocrine tumors detected with an extended marker panel

Aberrant methylation as a main mechanism of TSGs silencing in PTC

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