BACKGROUND & AIMS: Microsatellite instability was first described in hereditary nonpolyposis colorectal cancers and sporadic colorectal cancers, in which it was associated with a good prognosis. The aim of this study was to assess the advantages of a novel fluorescent assay for detecting microsatellite instability. METHODS: Eleven fluorescently tagged microsatellites and an automated DNA sequencer were used to investigate 54 sporadic colorectal adenocarcinomas. RESULTS: This fluorescent assay combined accurate allele sizing with cross-sectional data display and allowed improved assessment of microsatellite instability. Twenty-two percent of cancers (12 of 54) showed microsatellite instability with at least one marker. For tumors showing microsatellite instability, results were obtained for a minimum of eight markers. Six tumors showed microsatellite instability at high frequency (at least 63% of markers affected), and 42% of the patients who had a tumor showing microsatellite instability had a synchronous and/or metachronous colorectal tumor (vs. 7% of patients whose tumor did not show microsatellite instability). Patients with a microsatellite instability-positive tumor had an improved prognosis (P = 0.03). CONCLUSIONS: The use of this fluorescent assay improved the assessment of microsatellite instability with the automated analysis and cross-sectional data display. The assay identified a subgroup of patients who showed microsatellite instability and who also showed clinical features that differed from the microsatellite instability-negative cases.
BACKGROUND & AIMS: Microsatellite instability was first described in hereditary nonpolyposis colorectal cancers and sporadic colorectal cancers, in which it was associated with a good prognosis. The aim of this study was to assess the advantages of a novel fluorescent assay for detecting microsatellite instability. METHODS: Eleven fluorescently tagged microsatellites and an automated DNA sequencer were used to investigate 54 sporadic colorectal adenocarcinomas. RESULTS: This fluorescent assay combined accurate allele sizing with cross-sectional data display and allowed improved assessment of microsatellite instability. Twenty-two percent of cancers (12 of 54) showed microsatellite instability with at least one marker. For tumors showing microsatellite instability, results were obtained for a minimum of eight markers. Six tumors showed microsatellite instability at high frequency (at least 63% of markers affected), and 42% of the patients who had a tumor showing microsatellite instability had a synchronous and/or metachronous colorectal tumor (vs. 7% of patients whose tumor did not show microsatellite instability). Patients with a microsatellite instability-positive tumor had an improved prognosis (P = 0.03). CONCLUSIONS: The use of this fluorescent assay improved the assessment of microsatellite instability with the automated analysis and cross-sectional data display. The assay identified a subgroup of patients who showed microsatellite instability and who also showed clinical features that differed from the microsatellite instability-negative cases.
Authors: Mine S Cicek; Noralane M Lindor; Steven Gallinger; Bharati Bapat; John L Hopper; Mark A Jenkins; Joanne Young; Daniel Buchanan; Michael D Walsh; Loic Le Marchand; Terrilea Burnett; Polly A Newcomb; William M Grady; Robert W Haile; Graham Casey; Sarah J Plummer; Lisa A Krumroy; John A Baron; Stephen N Thibodeau Journal: J Mol Diagn Date: 2011-05 Impact factor: 5.568
Authors: L Cawkwell; S Gray; H Murgatroyd; F Sutherland; L Haine; M Longfellow; S O'Loughlin; D Cross; O Kronborg; C Fenger; N Mapstone; M Dixon; P Quirke Journal: Gut Date: 1999-09 Impact factor: 23.059
Authors: Vanessa Deschoolmeester; Marc Baay; Wim Wuyts; Eric Van Marck; Paul Pelckmans; Filip Lardon; Jan B Vermorken Journal: J Clin Lab Anal Date: 2006 Impact factor: 2.352