UNLABELLED: Tumour microsatellite instability (MSI) is useful in identifying patients with hereditary non-polyposis colorectal cancer (HNPCC) with defective DNA mismatch repair (MMR) genes. A reference Bethesda panel has limitations resulting from the inclusion of dinucleotide markers, which are less sensitive and specific for detection of tumours with MMR deficiencies. We developed a multiplex PCR assay with additional four mononucleotide markers and one dinucleotide marker (NR-21, NR-24, BAT-40, TGF-BetaR and D18S58) for a rapid and proper classification of MSI-H, MSI-L and MSS colorectal cancers. Two tetranucleotide markers were added to identify sample mix-ups and/or contamination. RESULTS: all the 44 cases test cases were in agreement with previous classification except for three cases: one case MSI-H-Bethesda unstable only for dinucleotides markers shifted to MSI-L category and two cases MSI-L-Bethesda unstable for mononucleotide markers shifted to MSI-H category. Immunohistochemistry analysis revealed that these two MSI-H cases did not expressed hMLH1 and they were found to be methylated at the MLH1 promoter, while the first one that shifted to MSI-L showed MMR protein expression. CONCLUSION: a complete panel of ten markers including four dinucleotide and six mononucleotide microsatellites allows accurate evaluation of tumor MSI status.
UNLABELLED: Tumour microsatellite instability (MSI) is useful in identifying patients with hereditary non-polyposis colorectal cancer (HNPCC) with defective DNA mismatch repair (MMR) genes. A reference Bethesda panel has limitations resulting from the inclusion of dinucleotide markers, which are less sensitive and specific for detection of tumours with MMR deficiencies. We developed a multiplex PCR assay with additional four mononucleotide markers and one dinucleotide marker (NR-21, NR-24, BAT-40, TGF-BetaR and D18S58) for a rapid and proper classification of MSI-H, MSI-L and MSS colorectal cancers. Two tetranucleotide markers were added to identify sample mix-ups and/or contamination. RESULTS: all the 44 cases test cases were in agreement with previous classification except for three cases: one case MSI-H-Bethesda unstable only for dinucleotides markers shifted to MSI-L category and two cases MSI-L-Bethesda unstable for mononucleotide markers shifted to MSI-H category. Immunohistochemistry analysis revealed that these two MSI-H cases did not expressed hMLH1 and they were found to be methylated at the MLH1 promoter, while the first one that shifted to MSI-L showed MMR protein expression. CONCLUSION: a complete panel of ten markers including four dinucleotide and six mononucleotide microsatellites allows accurate evaluation of tumor MSI status.
Authors: E Urso; M Agostini; S Pucciarelli; M Rugge; R Bertorelle; I Maretto; C Bedin; E D'Angelo; C Mescoli; M Zorzi; A Viel; G Bruttocao; B Ferraro; F Erroi; P Contin; G L De Salvo; D Nitti Journal: Tumour Biol Date: 2012-01-26
Authors: Jennifer B Goldstein; William Wu; Ester Borras; Gita Masand; Amanda Cuddy; Maureen E Mork; Sarah A Bannon; Patrick M Lynch; Miguel Rodriguez-Bigas; Melissa W Taggart; Ji Wu; Paul Scheet; Scott Kopetz; Y Nancy You; Eduardo Vilar Journal: Clin Cancer Res Date: 2017-05-18 Impact factor: 12.531
Authors: E Urso; M Agostini; S Pucciarelli; C Bedin; E D'angelo; C Mescoli; A Viel; I Maretto; I Mammi; D Nitti Journal: Mol Biol Rep Date: 2012-07-11 Impact factor: 2.316