<b>
                     <i>BRAF</i>
                  </b> Mutation Is Frequently Present in Sporadic Colorectal Cancer with Methylated hMLH1, But Not in Hereditary Nonpolyposis Colorectal Cancer

Deng, Guoren; Bell, Ian M.; Crawley, Suzanne C.; Gum, James R.; Terdiman, Jonathan P.; Allen, Brian; Truta, Brindusa; Sleisenger, Marvin H.; Kim, Young S.

doi:10.1158/1078-0432.ccr-1118-3

Cited by 371 publications

(292 citation statements)

References 10 publications

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“…Cell line LoVo was chosen on the basis of literature data indicating that LoVo cells harbor a K-ras point mutation at codon 13. [23][24][25] As a control cell line, HT29 (91072201 ECACC, Porton Down, UK) cell with WT K-ras were selected. 26 They were grown in Advanced Eagle's minimum essential medium (Gibco) supplemented with 2% fetal bovine serum (Gibco), 2 mM L-glutamine, 1 mM sodium pyruvate and 350 mg l À1 gentamicin and 1 ml l À1 crystacillin.…”

Section: Colorectal Tumor Cell Linementioning

confidence: 99%

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

et al. 2010

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Mutations of K-ras have been found in 30-60% of colorectal carcinomas and are believed to be associated with tumor initiation, tumor progression and metastasis formation. Therefore, silencing of mutant K-ras expression has become an attractive therapeutic strategy for colorectal cancer treatment. The aim of our study was to investigate the effect of microRNA (miRNA) molecules directed against K-ras (miRNA-K-ras) on K-ras expression level and the growth of colorectal carcinoma cell line LoVo in vitro and in vivo. In addition, we evaluated electroporation as a gene delivery method for transfection of LoVo cells and tumors with plasmid DNA encoding miRNA-K-ras (pmiRNA-K-ras). Results of our study indicated that miRNAs targeting K-ras efficiently reduced K-ras expression and cell survival after in vitro electrotransfection of LoVo cells with pmiRNA-K-ras. In vivo, electroporation has proven to be a simple and efficient delivery method for local administration of pmiRNA-K-ras molecules into LoVo tumors. This therapy shows pronounced antitumor effectiveness and has no side effects. The obtained results demonstrate that electrogene therapy with miRNA-K-ras molecules can be potential therapeutic strategy for treatment of colorectal cancers harboring K-ras mutations.

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Section: Colorectal Tumor Cell Linementioning

confidence: 99%

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

et al. 2010

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“…This mutation is strongly associated with MLH1 inactivation secondary to promoter hypermethylation. [10][11][12][13][14][15] It has been used to distinguish LS-associated from sporadic MSI-positive tumors. 10,11,[16][17][18][19][20][21] The lack of BRAF mutations identifies with high sensitivity (96-100%) and lower specificity (22-100%) CRC cases associated with LS.…”

Section: Introductionmentioning

confidence: 99%

“…[10][11][12][13][14][15] It has been used to distinguish LS-associated from sporadic MSI-positive tumors. 10,11,[16][17][18][19][20][21] The lack of BRAF mutations identifies with high sensitivity (96-100%) and lower specificity (22-100%) CRC cases associated with LS. 10,11,[16][17][18][19][20][21] Occasionally, BRAF mutations have been detected in LS patients.…”

Section: Introductionmentioning

confidence: 99%

“…10,11,[16][17][18][19][20][21] The lack of BRAF mutations identifies with high sensitivity (96-100%) and lower specificity (22-100%) CRC cases associated with LS. 10,11,[16][17][18][19][20][21] Occasionally, BRAF mutations have been detected in LS patients. 22 Methylation of the MLH1 promoter, leading to a loss of MLH1 expression, is also strongly associated with sporadic MSI-positive CRCs.…”

Section: Introductionmentioning

confidence: 99%

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MLH1 promoter hypermethylation in the analytical algorithm of Lynch syndrome: a cost-effectiveness study

et al. 2012

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The analytical algorithm of Lynch syndrome (LS) is increasingly complex. BRAF V600E mutation and MLH1 promoter hypermethylation have been proposed as a screening tool for the identification of LS. The aim of this study was to assess the clinical usefulness and cost-effectiveness of both somatic alterations to improve the yield of the diagnostic algorithm of LS. A total of 122 colorectal tumors from individuals with family history of colorectal cancer that showed microsatellite instability and/or loss of mismatch repair (MMR) protein expression were studied. MMR germline mutations were detected in 57 cases (40 MLH1, 15 MSH2 and 2 MSH6). BRAF V600E mutation was assessed by single-nucleotide primer extension. MLH1 promoter hypermethylation was assessed by methylation-specific multiplex ligation-dependent probe amplification in a subset of 71 cases with loss of MLH1 protein. A decision model was developed to estimate the incremental costs of alternative case-finding methods for detecting MLH1 mutation carriers. One-way sensitivity analysis was performed to assess robustness of estimations. Sensitivity of the absence of BRAF mutations for depiction of LS patients was 96% (23/24) and specificity was 28% (13/47). Specificity of MLH1 promoter hypermethylation for depiction of sporadic tumors was 66% (31/47) and sensitivity of 96% (23/24). The cost per additional mutation detected when using hypermethylation analysis was lower when compared with BRAF study and germinal MLH1 mutation study. Somatic hypermethylation of MLH1 is an accurate and cost-effective pre-screening method in the selection of patients that are candidates for MLH1 germline analysis when LS is suspected and MLH1 protein expression is absent.

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“…[2][3][4][5] MLH1 methylation occurs in close association with the presence of the oncogenic BRAF V600E mutation in sporadic colorectal cancer. 6 The c.-93G4A SNP (rs1800734) within the MLH1 promoter has been associated with an increased risk of microsatellite instability or MLH1 methylation in some colorectal and endometrial cancer populations, but not in others. [7][8][9][10] However, these associations have been disputed on the basis that linkage disequilibrium with pathogenic mutations could not be ruled out in populations with a high incidence of familial cancer.…”

mentioning

confidence: 99%

Methylation of the 3p22 region encompassing MLH1 is representative of the CpG island methylator phenotype in colorectal cancer

et al. 2011

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Epigenetic silencing of cancer-related genes by promoter methylation is a frequent event in sporadic colorectal cancer. The CpG island methylator phenotype (CIMP þ ), in which discrete genes throughout the genome are simultaneously methylated, and long-range epigenetic silencing, whereby multiple genes within contiguous chromosomal regions are methylated, have been described in subsets of colorectal cancer. We previously reported the concurrent methylation of the mismatch repair gene MLH1 with a cluster of flanking genes in chromosome region 3p22 in sporadic colorectal carcinoma exhibiting microsatellite instability and the BRAF V600E mutation. Herein, we aimed to determine whether methylation of MLH1 and neighbouring 3p22 genes, singly or concomitantly, correlate with the germline c.-93G4A SNP within the MLH1 promoter, CIMP þ and other clinicopathological and molecular features of the tumours. By studying a cohort of 946 sporadic colorectal cancer cases, we show a strong association between concordant methylation of Z3 of five 3p22 genes with CIMP þ and the BRAF V600E mutation (Po0.001). These associations were independent of microsatellite instability, as concomitant methylation of 3p22 genes other than MLH1 was found in microsatellite stable cancers. These findings show that long-range epigenetic silencing across 3p22 occurs in the context of CIMP þ and the BRAF V600E mutation, and only gives rise to microsatellite instability when this process encompasses MLH1. Furthermore, the strong relationship between long-range epigenetic silencing of 3p22 and CIMP þ provides further evidence that these two purportedly distinct epigenetic phenotypes represent a single entity with a common aetiology. Low-level methylation of MLH1 and flanking 3p22 genes, as well as the BRAF V600E mutation, were detected in the apparently normal colonic mucosa of a small number of cases whose tumours showed a similar molecular profile, suggesting that these concurring genetic and epigenetic events can occur as a field defect in neoplastic development.

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BRAF Mutation Is Frequently Present in Sporadic Colorectal Cancer with Methylated hMLH1, But Not in Hereditary Nonpolyposis Colorectal Cancer

Cited by 371 publications

References 10 publications

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

MLH1 promoter hypermethylation in the analytical algorithm of Lynch syndrome: a cost-effectiveness study

Methylation of the 3p22 region encompassing MLH1 is representative of the CpG island methylator phenotype in colorectal cancer

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