Immunohistochemistry Identifies Carriers of Mismatch Repair Gene Defects Causing Hereditary Nonpolyposis Colorectal Cancer

Stormorken, Astrid; Bowitz-Lothe, Inger Marie; Noren, Tove; Kure, Elin H.; Aase, Steinar; Wijnen, Juul T.; Apold, Jaran; Heimdal, Ketil; Møller, Pål

doi:10.1200/jco.2005.05.180

Cited by 39 publications

(43 citation statements)

References 42 publications

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“…This suggested that the cutoff values are required in both functional level and protein level for overall evaluation. Recent studies have indicated that the immunohistochemical analysis of MMR proteins is one of the most efficient and sensitive screening method to detect abnormalities in MMR proteins (40,41). In our data, in vitro MMR activities were impaired without reducing MLH1 protein levels in some MLH1 missense variants.…”

Section: Discussionsupporting

confidence: 48%

Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays

et al. 2007

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The functional characterization of nonsynonymous single nucleotide polymorphisms in human mismatch repair (MMR) genes has been critical to evaluate their pathogenicity for hereditary nonpolyposis colorectal cancer. We previously established an assay for detecting loss-of-function mutations in the MLH1 gene using a dominant mutator effect of human MLH1 expressed in Saccharomyces cerevisiae. The purpose of this study is to extend the functional analyses of nonsynonymous single nucleotide polymorphisms in the MLH1 gene both in quality and in quantity, and integrate the results to evaluate the variants for pathogenic significance. The 101 MLH1 variants, which covered most of the reported MLH1 nonsynonymous single nucleotide polymorphisms and consisted of one 3-bp deletion, 1 nonsense and 99 missense variants, were examined for the dominant mutator effect by three yeast assays and for the ability of the variant to repair a heteroduplex DNA with mismatch bases by in vitro MMR assay. There was diversity in the dominant mutator effects and the in vitro MMR activities among the variants. The majority of functionally inactive variants were located around the putative ATP-binding pocket of the NH 2 -terminal domain or the whole region of the COOH-terminal domain. Integrated functional evaluations contribute to a better prediction of the cancer risk in individuals or families carrying MLH1 variants and provide insights into the function-structure relationships in MLH1. [Cancer Res 2007;67(10):4595-604]

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Section: Discussionsupporting

confidence: 48%

Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays

et al. 2007

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“…With a reliable immunohistochemical method, in most cases, only the mutated gene would be screened. This methodology has recently been demonstrated to be useful in the identification of carriers of mutations in the mismatch repair genes associated with hereditary non-polyposis colorectal cancer (Stormorken et al 2005).…”

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confidence: 99%

Familial Breast/Ovarian Cancer and BRCA1/2 Genetic Screening: The Role of Immunohistochemistry as an Additional Method in the Selection of Patients

Vaz¹,

Machado²,

Brandão³

et al. 2007

J Histochem Cytochem.

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S U M M A R Y Only 20-25% of families screened for BRCA1/2 mutations are found positive. Because only a positive result is informative, we studied the role of BRCA1/2 immunohistochemistry as an additional method for patient selection. From 53 high-risk-affected probands, 18 (34%) had available paraffin blocks of their tumors and were selected for this study. Mutation screening was done by conformation-sensitive gel electrophoresis and multiplex ligation-dependent probe amplification. For immunohistochemistry, 21 neoplastic specimens (15 breast carcinomas, 5 ovary neoplasms, and 1 rectal adenocarcinoma) were analyzed with BRCA1 (monoclonal antibody, Ab-1, oncogene) and BRCA2 (polyclonal antibody, Ab-2, oncogene) antibodies. Absence of the BRCA1 protein was confirmed in negative tumors by Western blotting. Seven patients were positive for BRCA1/2 mutations: 5 for BRCA1 and 2 for BRCA2. Four out of five positive patients had tumors negative for BRCA1 immunostaining, and the remaining 13 BRCA1-negative patients had positive BRCA1 immunostaining in all tumor samples. Sensitivity to predict for BRCA1 mutation carriers was 80%, and specificity was 100%, with a positive predictive value of 100% and a negative predictive value of 93%. This correlation was statistically significant ( p50.001). No correlation was observed for BRCA2. If larger studies confirm these results, high-risk patients with BRCA1-negative tumors should be screened first for this gene. (J Histochem Cytochem 55:1105-1113, 2007

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“…Therefore, by revealing the presence of MLH1 or MSH2 LOH in an MSI-positive tumor, our method could eliminate further need for IHC analysis and appreciably lower the cost of prescreening in a nonnegligible percentage of cases. This approach could be especially useful when technical difficulties arise in the execution and/or interpretation of IHC assays (32)(33)(34)(35)(36)(37). The final results of IHC analyses are influenced by several factors, including those related to preparing the FFPE sample (type of fixative, fixation times, temperatures reached during the embedding procedure).…”

Section: Discussionmentioning

confidence: 99%

Multiplex SNaPshot Genotyping for Detecting Loss of Heterozygosity in the Mismatch-Repair Genes MLH1 and MSH2 in Microsatellite-Unstable Tumors

et al. 2008

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BACKGROUND:In the workup of patients with suspected hereditary nonpolyposis colorectal cancer (HNPCC), detection of loss of heterozygosity (LOH) could help pinpoint the mismatch-repair (MMR) gene carrying the germline mutation, but analysis of microsatellite markers has proved unreliable for this purpose. We developed a simple, low-cost method based on singlenucleotide polymorphism (SNP) genotyping and capillary electrophoresis for the assessment of LOH at 2 MMR loci simultaneously.

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Immunohistochemistry Identifies Carriers of Mismatch Repair Gene Defects Causing Hereditary Nonpolyposis Colorectal Cancer

Abstract: Wide clinical criteria to select HNPCC kindreds, followed by immunohistochemistry of tumor material from one affected person in each family, had high sensitivity and specificity to predict MMR mutations.

Cited by 39 publications

References 42 publications

Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays

Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays

Familial Breast/Ovarian Cancer and BRCA1/2 Genetic Screening: The Role of Immunohistochemistry as an Additional Method in the Selection of Patients

Multiplex SNaPshot Genotyping for Detecting Loss of Heterozygosity in the Mismatch-Repair Genes MLH1 and MSH2 in Microsatellite-Unstable Tumors

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