Evaluation of Micro Satellite Instability and Mismatch Repair Status in Different Solid Tumors: A Multicenter Analysis in a Real World Setting

Cells. 2021 Jul 24;10(8):1878. doi: 10.3390/cells10081878.


Immune-checkpoint inhibitors (ICIs) play a key role in the treatment of advanced stage colorectal cancer (CRC) patients featuring a deficient DNA mismatch repair (dMMR) system or a high microsatellite instability (MSI-H) profile. However, beyond the established role in CRC patients, ICIs have highly proven efficacy in other solid tumors featuring MSI-H/dMMR status represented by endometrial, gastric, ovarian, prostatic, and pancreatic carcinomas (EC, GC, OC, PrC, and PaC). Our aim was to compare the concordance rates among the Idylla™ MSI test, TapeStation 4200, and immunohistochemical (IHC) analysis in assessing MSI-H/dMMR status in EC, GC, OC, PrC, and PaC patients. The Sanger sequencing-based Titano MSI test was used in discordant cases. One hundred and eighty-five cases (n = 40 PrC, n = 39 GC, n = 38 OC, n = 35 PaC, and n = 33 EC) were retrospectively selected. MMR protein expression was evaluated by IHC. After DNA quality and quantity evaluations, the IdyllaTM and TapeStation 4200 platforms were adopted for the evaluation of MSI status. Remarkably, compared to IHC, the Idylla™ platform achieved a global concordance rate of 94.5% (154/163) for the microsatellite stable (MSS)/proficient MMR (pMMR) cases and 77.3% (17/22) for the MSI-H/dMMR cases. Similarly, a global concordance rate of 91.4% (149/163) and 68.2% (15/22) for MSS/pMMR and MSI-H/dMMR cases was also identified between IHC and the TapeStation 4200 microfluidic system. In addition, a global concordance of 93.1% (148/159) and 69.2% (18/26) for MSS/pMMR and MSI-H/dMMR cases was observed between the Idylla™ and TapeStation 4200 platforms. Discordant cases were analyzed using the Titano MSI kit. Overall, our data pinpointed a central role for molecular techniques in the diagnostic evaluation of dMMR/MSI-H status not only in CRC patients but also in other types of solid tumors.

Keywords: IHC; MMR; MSI; fully automated RT-PCR; immune checkpoint inhibitors (ICIs); immunotherapy; microfluidic; predictive molecular pathology.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers, Tumor / analysis
  • DNA Mismatch Repair*
  • DNA Repair Enzymes / analysis
  • Digestive System Neoplasms / enzymology
  • Digestive System Neoplasms / genetics*
  • Digestive System Neoplasms / pathology
  • Endometrial Neoplasms / enzymology
  • Endometrial Neoplasms / genetics
  • Endometrial Neoplasms / pathology
  • Female
  • Genital Neoplasms, Female / enzymology
  • Genital Neoplasms, Female / genetics*
  • Genital Neoplasms, Female / pathology
  • Humans
  • Immunohistochemistry
  • Italy
  • Male
  • Microfluidic Analytical Techniques
  • Microsatellite Instability*
  • Molecular Diagnostic Techniques
  • Ovarian Neoplasms / enzymology
  • Ovarian Neoplasms / genetics
  • Ovarian Neoplasms / pathology
  • Pancreatic Neoplasms / enzymology
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / pathology
  • Polymerase Chain Reaction
  • Predictive Value of Tests
  • Prostatic Neoplasms / enzymology
  • Prostatic Neoplasms / genetics*
  • Prostatic Neoplasms / pathology
  • Reproducibility of Results
  • Retrospective Studies
  • Stomach Neoplasms / enzymology
  • Stomach Neoplasms / genetics
  • Stomach Neoplasms / pathology


  • Biomarkers, Tumor
  • DNA Repair Enzymes