Detection of microsatellite instability in a panel of solid tumours with the Idylla MSI Test using extracted DNA

J Clin Pathol. 2021 Jan;74(1):36-42. doi: 10.1136/jclinpath-2020-206581. Epub 2020 Jun 8.

Abstract

Aim: During the last few years, determination of microstatellite instability (MSI) status has become a routine part of clinical practice, essentially to detect Lynch syndrome. Recently, MSI testing has increased with the development of immunotherapy and has expanded to a large panel of solid tumours. The aim of our work was to evaluate a fully automated system developed by Biocartis, the Idylla MSI Test, which performs an MSI analysis within 150 min.

Methods: A comparison between pentaplex PCR, immunohistochemistry and Idylla MSI Test was performed in 53 colorectal carcinoma samples, 7 small intestine adenocarcinomas, 15 duodenal and pancreatic adenocarcinomas, 16 gastric tumours, 15 endometrial adenocarcinomas, 5 ovarian carcinomas and 4 cases of urinary tract tumours using extracted DNA. Limit-of-detection (LOD) experiment was also done using a commercial DNA known to harbour MSI phenotype.

Results: The overall sensitivity was 94% and the overall specificity was 100%. Two invalid and three false-negative results were observed. Our experiments showed that the amount of DNA loaded into the cartridge was decisive and should be superior to 25 ng. LOD comprised between 4% and 8%.

Conclusion: Overall, we have demonstrated that the Idylla MSI Test is a rapid and valid option to detect MSI phenotype which can be used in a large panel of solid tumours.

Keywords: DNA; colorectal neoplasms; molecular; pancreatic neoplasms; pathology; stomach neoplasms.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Adult
  • Carcinoma / genetics*
  • Colorectal Neoplasms, Hereditary Nonpolyposis / genetics*
  • DNA, Neoplasm / analysis
  • Endometrial Neoplasms / genetics*
  • Female
  • Humans
  • Immunohistochemistry
  • Microsatellite Instability*
  • Ovarian Neoplasms / genetics*
  • Pancreatic Neoplasms / genetics*
  • Phenotype
  • Polymerase Chain Reaction
  • Stomach Neoplasms / genetics*

Substances

  • DNA, Neoplasm