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Updated: Jun 16, 2026
Detection of a Circulating MicroRNA Custom Panel in Patients with Metastatic Colorectal Cancer
Published on: March 14, 2019
A ten markers panel provides a more accurate and complete microsatellite instability analysis in mismatch
Marco Agostini1, Maria Vittoria Enzo, Luca Morandi
1II Section of Surgery Clinic, Department Oncologic and Surgical Sciences, University of Padova, Padova, Italy. m.agostini@unipd.it
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.
